diff options
Diffstat (limited to 'taccle')
| -rw-r--r-- | taccle/COPYING | 340 | ||||
| -rw-r--r-- | taccle/ChangeLog | 48 | ||||
| -rw-r--r-- | taccle/README.md | 123 | ||||
| -rw-r--r-- | taccle/examples/Makefile | 17 | ||||
| -rw-r--r-- | taccle/examples/if_then_else.tac | 18 | ||||
| -rw-r--r-- | taccle/examples/infix_calc.tac | 35 | ||||
| -rw-r--r-- | taccle/examples/interactive_calculator.tac | 42 | ||||
| -rw-r--r-- | taccle/examples/lalr_reduce_reduce.tac | 18 | ||||
| -rw-r--r-- | taccle/examples/reduce_reduce.tac | 20 | ||||
| -rw-r--r-- | taccle/examples/reduce_reduce2.tac | 15 | ||||
| -rw-r--r-- | taccle/examples/shift_reduce.tac | 17 | ||||
| -rw-r--r-- | taccle/examples/shift_reduce2.tac | 20 | ||||
| -rw-r--r-- | taccle/examples/simple_calculator.tac | 36 | ||||
| -rw-r--r-- | taccle/examples/simple_expressions.tac | 30 | ||||
| -rw-r--r-- | taccle/examples/simple_grammar.tac | 27 | ||||
| -rw-r--r-- | taccle/examples/simple_scanner.fcl | 16 | ||||
| -rw-r--r-- | taccle/taccle.tcl | 1726 |
17 files changed, 0 insertions, 2548 deletions
diff --git a/taccle/COPYING b/taccle/COPYING deleted file mode 100644 index d60c31a..0000000 --- a/taccle/COPYING +++ /dev/null @@ -1,340 +0,0 @@ - GNU GENERAL PUBLIC LICENSE - Version 2, June 1991 - - Copyright (C) 1989, 1991 Free Software Foundation, Inc. - 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA - Everyone is permitted to copy and distribute verbatim copies - of this license document, but changing it is not allowed. - - Preamble - - The licenses for most software are designed to take away your -freedom to share and change it. By contrast, the GNU General Public -License is intended to guarantee your freedom to share and change free -software--to make sure the software is free for all its users. This -General Public License applies to most of the Free Software -Foundation's software and to any other program whose authors commit to -using it. (Some other Free Software Foundation software is covered by -the GNU Library General Public License instead.) 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Of course, the commands you use may -be called something other than `show w' and `show c'; they could even be -mouse-clicks or menu items--whatever suits your program. - -You should also get your employer (if you work as a programmer) or your -school, if any, to sign a "copyright disclaimer" for the program, if -necessary. Here is a sample; alter the names: - - Yoyodyne, Inc., hereby disclaims all copyright interest in the program - `Gnomovision' (which makes passes at compilers) written by James Hacker. - - <signature of Ty Coon>, 1 April 1989 - Ty Coon, President of Vice - -This General Public License does not permit incorporating your program into -proprietary programs. If your program is a subroutine library, you may -consider it more useful to permit linking proprietary applications with the -library. If this is what you want to do, use the GNU Library General -Public License instead of this License. diff --git a/taccle/ChangeLog b/taccle/ChangeLog deleted file mode 100644 index e9728f1..0000000 --- a/taccle/ChangeLog +++ /dev/null @@ -1,48 +0,0 @@ -2005-03-17 J. Tang <tang@jtang.org> - - * Added infinite recursion detection. It should work. - -2004-10-29 J. Tang <tang@jtang.org> - - * Added more comments; upped version to 1.0. - -2004-09-29 J. Tang <tang@jtang.org> - - * Added --version flag to display taccle version. - - * Added infix_calc.tac as example of how to do precedence. - - * Added operator precedence (%left, %right, %nonassoc, and - %prec). Seems to work, at least with the example from the bison - info manual. - -2004-09-28 J. Tang <tang@jtang.org> - - * Discovered obscure error when calculating FIRST and FOLLOW sets - given a rule of the form: x -> A x A - (i.e., when the rule recurses with a terminal following the lhs - token) - - * Added -w to enable warnings display. - -2004-09-27 J. Tang <tang@jtang.org> - - * Added write_array procedure to better format state transition - tables. Thanks to jcw for suggestion. - -2004-09-08 J. Tang <tang@jtang.org> - - * As a result of working epsilons, added embedded actions. - - * Fixed epsilon transitions by adding FOLLOW sets. Double Woot! - -2004-08-18 J. Tang <tang@jtang.org> - - * Added epsilon transitions. Woot! - - * Renamed synthesized attributes to just $1, $2... Renamed $yy_ - to $_. (Yup, $_ like in Perl.) Thanks to Matt Newman for - suggestion. - - * Added error terminal and error recovery (though no yyerrok). - See interactive_calculator.tac example. diff --git a/taccle/README.md b/taccle/README.md deleted file mode 100644 index 19609e9..0000000 --- a/taccle/README.md +++ /dev/null @@ -1,123 +0,0 @@ -Copyright ---------- -taccle itself is protected by the GNU General Public License. See the -file COPYING for details. Of course, any code you generate using -taccle is subject to whatever restrictions you place on it. - - -Availability ------------- -A wiki page for taccle may be found at http://mini.net/tcl/taccle. -An archive of taccle files are available at http://tcl.jtang.org/taccle. - - -taccle README -------------- -taccle is another compiler compiler for the Tcl language. It takes as -input a "taccle specification file"; from this taccle generates a Tcl -file that implements an LALR(1) parser. The program brings to the Tcl -language what yacc and bison do for C and C++. - -This release of taccle implements nearly all features of yacc: - - #include filename - - %define parse.error verbose declaration - - %token and %start declarations - - epsilon transitions (i.e., "empty" rules) - - embedded (mid-rule) actions - - literal tokens - - symbol values and synthesized attributes - - the error token and error recovery - - shift/reduce and reduce/reduce conflict notification - - operator precedence with %left, %right, %nonassoc, and %prec - - functions yyerror, YYABORT, YYACCEPT, and yyclearin - - infinite recursion detection - -Features currently missing in taccle are: - - inherited attributes - -Because taccle uses the lset command it requires Tcl 8.4 or greater. - -Be aware of the following differences between taccle and yacc: - -1. taccle (and Tcl) has no concept of variable types. Thus %union and - %type declarations are no longer needed. - -2. yacc uses variables $1, $2, etc for symbol values; it uses $$ for - the synthesized attribute. Although both $1 and $$ are legal - variable references in Tcl the latter is more awkward; the - expression `set $ foo' is not legal. Instead of $$ use the name - '_', as in `set _ foo'. These variables' scopes are valid only - within the context of an action. See - examples/simple_calculator.tac for an example. - - (The astute observer notes that using $_ for synthesized values is - similar to Perl's use of the auto-variable $_.) - -3. taccle has error handling just like bison. It always declares the - terminal `error' that is pushed onto the stack whenever it detects - a syntax error. Although yyclearin is implemented neither - YYRECOVERING nor yyerrok are. The example - interactive_calculator.tac implements error handling. - -4. Like yacc, taccle requires a token generator. The examples use - fickle (http://mini.net/tcl/fickle), though others are welcome. - -5. taccle calls a global function yylex to fetch the next token. This - yylex function is expected to return the next token in the input - stream, either a string or a number. Normally this poses no - problem except for the case of a literal zero. Tcl makes no - distinction between the integer zero and the string zero. Because - zero is reserved for the end of input marker, taccle will refuse - grammars that employ literal zeros. You can get around this by - declaring `%token ZERO' and using that instead. - -6. Another literal that causes all sorts of problems is the open brace - '{'. Because most things are represented internally as lists the - presence of the brace breaks everything. Thus taccle will refuse - to parse grammars with this literal; you'll have to use a %token - instead. - - -Using the Examples ------------------- -Execute taccle as if it were yacc: - - $ tclsh ./taccle.tcl -d some_spec_file.tac - -This will generate two files, some_spec_file.tcl and -some_spec_file.tab.tcl. The first contains the actual parser code; -execute it by calling yyparse. The latter file is file to be sourced -by the lexer, much akin to yacc's y.tab.h file. - -The Makefile in the examples subdirectory will generate two simple -calculator programs. You will need a copy of fickle (available at -http://mini.net/tcl/fickle) and may need to modify its location on -line 4 of the Makefile. After filtering simple_calculator through -ficcle and taccle execute it like so: - - $ echo "6*9" | tclsh simple_calculator.tcl - -If all goes well the program displays: - - Result is 54 - -A more interesting example is interactive_calculator.tcl. This one is -designed to handle any arbitrary number of commands. Upon errornous -equations it recovers by discarding the rest of the buffer. Here is -an example session of it: - - $ tclsh interactive_calculator.tcl - 6*9 - = 54 - 1++2++3 - = error - 1 + 2 + 3 - = 6 - -The final example, infix_calc.tcl, shows how to use operator -precedence to resolve shift/reduce conflicts. It understands both -left associative operators (addition et al) as well as right -associative (exponentation). Here is an example use: - - $ echo "2^2^2 - 10 * 2 + 6 / 3" | tclsh infix_calc.tcl - -2 diff --git a/taccle/examples/Makefile b/taccle/examples/Makefile deleted file mode 100644 index 7235aea..0000000 --- a/taccle/examples/Makefile +++ /dev/null @@ -1,17 +0,0 @@ -# $Id: Makefile,v 1.2 2004/09/29 16:23:28 tang Exp $ - -TCL=tclsh -FICKLE=~/fickle/fickle.tcl -TACCLE=../taccle.tcl -EXAMPLES=interactive_calculator.tcl simple_calculator.tcl infix_calc.tcl - -all: $(EXAMPLES) simple_scanner.tcl - -%.tcl: %.fcl - $(TCL) $(FICKLE) $< - -%.tcl: %.tac - $(TCL) $(TACCLE) -d -v -w $< - -clean: - -rm -f *tcl *output diff --git a/taccle/examples/if_then_else.tac b/taccle/examples/if_then_else.tac deleted file mode 100644 index eee631a..0000000 --- a/taccle/examples/if_then_else.tac +++ /dev/null @@ -1,18 +0,0 @@ -# $Id: if_then_else.tac,v 1.1 2004/08/18 23:53:42 tang Exp $ - -# The classical if/then/else ambiguity. taccle resolves this by -# giving higher precedence to shifting else. -# -# References: -# Dragon book, page 250 -# lex & yacc, pages 233-235 - -%token IF ELSE TERMINAL - -%% - -stmt: IF '(' cond ')' stmt - | IF '(' cond ')' stmt ELSE stmt - | TERMINAL; - -cond: TERMINAL; diff --git a/taccle/examples/infix_calc.tac b/taccle/examples/infix_calc.tac deleted file mode 100644 index 95ef2ee..0000000 --- a/taccle/examples/infix_calc.tac +++ /dev/null @@ -1,35 +0,0 @@ -# $Id: infix_calc.tac,v 1.1 2004/09/29 16:23:28 tang Exp $ - -# This example demonstrates how taccle handles operator precedence. -# The code is shamelessly borrowed from the GNU Bison info manual. - -# taccle Declarations -%token ID NEWLINE -%left '-' '+' -%left '*' '/' -%left NEG # negation--unary minus -%right '^' # exponentiation - -# Grammar follows -%% -input: # empty string - | input line -; - -line: NEWLINE - | exp NEWLINE { puts [format "\t%.10g" $1] } -; - -exp: ID { set _ $1 } - | exp '+' exp { set _ [expr {$1 + $3}] } - | exp '-' exp { set _ [expr {$1 - $3}] } - | exp '*' exp { set _ [expr {$1 * $3}] } - | exp '/' exp { set _ [expr {$1 / $3}] } - | '-' exp %prec NEG { set _ [expr {-1.0 * $2}] } - | exp '^' exp { set _ [expr {pow($1, $3)}] } - | '(' exp ')' { set _ $2 } -; -%% - -source simple_scanner.tcl -yyparse diff --git a/taccle/examples/interactive_calculator.tac b/taccle/examples/interactive_calculator.tac deleted file mode 100644 index ac8a3ba..0000000 --- a/taccle/examples/interactive_calculator.tac +++ /dev/null @@ -1,42 +0,0 @@ -# $Id: interactive_calculator.tac,v 1.2 2004/09/08 21:38:44 tang Exp $ - -# This example expands the simple calculator to be interactive from -# the command line. Note the use of an empty rule (i.e., epsilon -# transition). Also featured are the error token and error recovery. - -%{ -#!/usr/bin/tclsh - -%} - -%token ID NEWLINE - -%% - -start: line NEWLINE start - | line - ; - -line: E { puts " = $1" } - | error { puts " -- error" } - | # empty - ; - -E: E '+' T { set _ [expr {$1 + $3}] } - | E '-' T { set _ [expr {$1 - $3}] } - | T - ; - -T: T '*' F { set _ [expr {$1 * $3}] } - | T '/' F { set _ [expr {$1 / $3}] } - | F - ; - -F: '(' E ')' { set _ $2 } - | ID { set _ $::yylval } - ; - -%% - -source simple_scanner.tcl -yyparse diff --git a/taccle/examples/lalr_reduce_reduce.tac b/taccle/examples/lalr_reduce_reduce.tac deleted file mode 100644 index fb7e493..0000000 --- a/taccle/examples/lalr_reduce_reduce.tac +++ /dev/null @@ -1,18 +0,0 @@ -# $Id: lalr_reduce_reduce.tac,v 1.1 2004/08/18 23:53:42 tang Exp $ - -# Below illustrates a grammar that is ambiguous by an LALR(1) parser -# but not an LR(1). There is a reduce/reduce conflict given a viable -# prefix ac. taccle resolves this by giving precedence to the first -# listed rule (A -> c). -# -# Reference: -# Dragon book, page 238 - -%token a b c d e - -%% - -S: a A d | b B d | a B e | b A e ; - -A: c ; -B: c ; diff --git a/taccle/examples/reduce_reduce.tac b/taccle/examples/reduce_reduce.tac deleted file mode 100644 index 4de6556..0000000 --- a/taccle/examples/reduce_reduce.tac +++ /dev/null @@ -1,20 +0,0 @@ -# $Id: reduce_reduce.tac,v 1.1 2004/08/18 23:53:43 tang Exp $ - -# This is an example of where a lookahead of just one symbol is -# insufficient. taccle finds a reduce/reduce conflict and resolves it -# by giving precedence to the first rule (cart_animal -> horse). -# -# Reference: -# lex & yacc, page 55 - -%token and cart plow horse goat ox - -%% - -phrase: cart_animal and cart - | work_animal and plow - ; - -cart_animal: horse | goat ; - -work_animal: horse | ox ; diff --git a/taccle/examples/reduce_reduce2.tac b/taccle/examples/reduce_reduce2.tac deleted file mode 100644 index 53c6d3b..0000000 --- a/taccle/examples/reduce_reduce2.tac +++ /dev/null @@ -1,15 +0,0 @@ -# $Id: reduce_reduce2.tac,v 1.1 2004/08/18 23:53:43 tang Exp $ - -# Here is another reduce/reduce conflict. -# -# Reference: -# lex & yacc, page 225 - -%token A B C Z - -%% - -start: A B x Z | y Z; - -x: C; -y: A B C; diff --git a/taccle/examples/shift_reduce.tac b/taccle/examples/shift_reduce.tac deleted file mode 100644 index 8905e26..0000000 --- a/taccle/examples/shift_reduce.tac +++ /dev/null @@ -1,17 +0,0 @@ -# $Id: shift_reduce.tac,v 1.1 2004/08/18 23:53:43 tang Exp $ - -# This is an example of a shift/reduce conflict. Eventually I will -# add operator precedence and associativity, but for now taccle simply -# gives higher precedence to shifts. -# -# Reference: -# lex & yacc, pages 229-230 and 236 - -%token TERMINAL - -%% - -expr: TERMINAL - | expr '+' expr - | expr '-' expr - | expr '*' expr ; diff --git a/taccle/examples/shift_reduce2.tac b/taccle/examples/shift_reduce2.tac deleted file mode 100644 index c3ad0d3..0000000 --- a/taccle/examples/shift_reduce2.tac +++ /dev/null @@ -1,20 +0,0 @@ -# $Id: shift_reduce2.tac,v 1.1 2004/08/18 23:53:43 tang Exp $ - -# Here is one final shift/reduce conflict. taccles resolves the -# problem by giving precedence to a shift. -# -# Reference: -# lex & yacc, pages 226-227 - -%token A R - -%% - -start: x1 - | x2 - | y R; - -x1: A R; -x2: A z; -y: A; -z: R; diff --git a/taccle/examples/simple_calculator.tac b/taccle/examples/simple_calculator.tac deleted file mode 100644 index ea104aa..0000000 --- a/taccle/examples/simple_calculator.tac +++ /dev/null @@ -1,36 +0,0 @@ -# $Id: simple_calculator.tac,v 1.1 2004/08/18 23:53:43 tang Exp $ - -# This example demonstrates symbol and synthesized values. - -%{ -#!/usr/bin/tclsh - -%} - -%token ID NEWLINE -%start start - -%% - -start: E NEWLINE { puts "Result is $1" } - | E { puts "Result is $1" } - ; - -E: E '+' T { set _ [expr {$1 + $3}] } - | E '-' T { set _ [expr {$1 - $3}] } - | T - ; - -T: T '*' F { set _ [expr {$1 * $3}] } - | T '/' F { set _ [expr {$1 / $3}] } - | F - ; - -F: '(' E ')' { set _ $2 } - | ID { set _ $::yylval } - ; - -%% - -source simple_scanner.tcl -yyparse diff --git a/taccle/examples/simple_expressions.tac b/taccle/examples/simple_expressions.tac deleted file mode 100644 index 7cc1f58..0000000 --- a/taccle/examples/simple_expressions.tac +++ /dev/null @@ -1,30 +0,0 @@ -# $Id: simple_expressions.tac,v 1.1 2004/08/18 23:53:43 tang Exp $ - -# This examples takes simple_grammar and adds actions to each rule. - -%{ -#!/usr/bin/tclsh - -%} - -%token ID -%start E - -%% - -E: E '+' T { puts "E + T" } - | T { puts "T" } - ; - -T: T '*' F { puts "T * F" } - | F { puts "F" } - ; - -F: '(' E ')' { puts "(E)" } - | ID { puts "id" } - ; - -%% - -source simple_scanner.tcl -yyparse diff --git a/taccle/examples/simple_grammar.tac b/taccle/examples/simple_grammar.tac deleted file mode 100644 index ea354d9..0000000 --- a/taccle/examples/simple_grammar.tac +++ /dev/null @@ -1,27 +0,0 @@ -# $Id: simple_grammar.tac,v 1.1 2004/08/18 23:53:43 tang Exp $ - -%{ - -source simple_scanner.tcl - -%} - -%token ID - -%% - -E: E '+' T - | T - ; - -T: T '*' F - | F - ; - -F: '(' E ')' - | ID - ; - -%% - -yyparse diff --git a/taccle/examples/simple_scanner.fcl b/taccle/examples/simple_scanner.fcl deleted file mode 100644 index 99ff67f..0000000 --- a/taccle/examples/simple_scanner.fcl +++ /dev/null @@ -1,16 +0,0 @@ -# $Id: simple_scanner.fcl,v 1.2 2004/08/18 23:55:31 tang Exp $ - -%{ -source "simple_calculator.tab.tcl" -%} - -%option interactive - -number [0-9]+ - -%% - -{number} { set ::yylval $yytext; return $::ID } -\n { return $::NEWLINE } -\s # ignore whitespace -. { set ::yylval $yytext; return $yytext } diff --git a/taccle/taccle.tcl b/taccle/taccle.tcl deleted file mode 100644 index d97a607..0000000 --- a/taccle/taccle.tcl +++ /dev/null @@ -1,1726 +0,0 @@ -#!/usr/bin/tclsh - -# $Id: taccle.tcl,v 1.6 2005/03/17 20:42:21 tang Exp $ - -set TACCLE_VERSION 1.3 - -# no yydebug -# no YYDEBUG -# no yyerrok -# no YYRECOVERING -# add %define parse.error verbose - -#//# -# Taccle is another compiler compiler written in pure Tcl. reads a -# <em>taccle specification file</em> to generate pure Tcl code that -# implements an LALR(1) parser. See the {@link README} file for -# complete instructions. Additional information may be found at -# {@link http://mini.net/tcl/taccle}. -# -# @author Jason Tang (tang@jtang.org) -#//# - -# Process a definition on a single line, either a literal block or a -# <code>%</code> directive. -# -# @param line text of a definition -proc handle_defs {line} { - # trim whitespace and remove any comments - set line [strip_comments [string trim $line]] - if {$line == ""} { - return - } - if {$line == "%\{"} { - handle_literal_block - } else { - # extract the keyword to the left of the first space and the - # arguments (if any) to the right - if {[regexp -line {^(\S+)\s+(.*)} $line foo keyword args] == 0} { - set keyword $line - set args "" - } - switch -- $keyword { - "%token" { - if {!$::parse_error} { - foreach {token_name} [split $args] { - if {$token_name != ""} { - # add the terminal token to the table - add_token $token_name $::TERMINAL 0 0 nonassoc - } - } - } else { - foreach {token_name token_title} [split $args] { - if {$token_name != {}} { - # add the terminal token to the table - set tt {} - if {$token_title != {}} { - set tt $token_title - } else { - set tt [string trimright $token_name {_}] - } - add_token $token_name $::TERMINAL 0 0 nonassoc $tt - } - } - } - } - "%left" - - "%right" - - "%nonassoc" { - handle_precedence $::next_precedence [string range $keyword 1 end] $args - incr ::next_precedence - } - "%start" { - if {$args == ""} { - taccle_error "Must supply a token with %start" $::PARAM_ERROR - } - set ::start_symbol $args - } - "%define" { - if {$args == {parse.error verbose}} { - set ::parse_error 1 - } - } - default { - taccle_error "Unknown declaration \"$keyword\"" $::SYNTAX_ERROR - } - } - } -} - -# Start reading from the source file and copy everything between ^%\{$ -# to ^%\}$ to the destination file. -proc handle_literal_block {} { - set end_defs 0 - set lines_in_block 0 - while {$end_defs == 0} { - if {[gets $::src line] < 0} { - taccle_error "No terminator to verbatim section found " $::SYNTAX_ERROR - } elseif {[string trim $line] == "%\}"} { - set end_defs 1 - } else { - puts $::dest $line - } - incr lines_in_block - } - incr ::line_count $lines_in_block -} - -# Assigns operator precedence to each token in $tokens. Adds the -# token as a TERMINAL to the token table. -# -# @param level integer value for token precedence -# @param direction direction of precedence, either <var>left</var>, -# <var>right</var>, or <var>nonassoc</var> -# @param tokens list of terminals to which assign precedence -proc handle_precedence {level direction tokens} { - foreach token $tokens { - if {[regexp -- {\A\'(.)\'\Z} $token foo c]} { - add_token $c $::TERMINAL 1 $level $direction - } else { - add_token $token $::TERMINAL 0 $level $direction - } - } -} - -# The nine steps to actually building a parser, given a string buffer -# containing all of the rules. -# -# @param rules_buf a very large string consisting of all of the -# grammar's rules -proc build_parser {rules_buf} { - # setp 0: parse the entire rules buffer into separate productions - handle_rules_buf $rules_buf - - # step 1: rewrite the grammar, then augment it - rewrite_grammar - - # step 2: determine which non-terminals are nullable - generate_nullable_table - - # step 3: generate FIRST table for each element in the token table - generate_first_table - - # step 4: now generate FOLLOW table for each element - generate_follow_table - - # step 5: build canonical LR(1) table - generate_lr1 - - # step 6: combine cores into LALR(1) table - generate_lalr1 - - # step 7: wherever there exists a shift/reduce conflict, choose to - # reduce wherever the precedence table dictates such - resolve_precedences - - # step 8: check for infinite recursions - check_recursions - - # step 9: finally take LALR(1) table and generate a state - # transition matrix - generate_lalr1_parse_table -} - -# Parses the rules buffer, extracting each rule and adding -# pseudo-rules wherever embedded actions exist. -# -# @param rules_buf remaining rules to handle -proc handle_rules_buf {rules_buf} { - # counts number of rules in the grammar - # rule number 0 is reserved for the special augmentation S' -> S - set ::rule_count 1 - set prev_lhs "" - - # keep track of pseudo-rules (used for embedded actions) - set pseudo_count 1 - - # add the special end marker - set ::token_table("\$",t) $::TERMINAL - set ::token_table("\$") 0 - set ::token_id_table(0) "\$" - set ::token_id_table(0,t) $::TERMINAL - set ::prec_table(0) 0 - set ::prec_table(0,dir) nonassoc - - # add the special error token - add_token error $::TERMINAL 1 0 nonassoc - - while {[string length $rules_buf] > 0} { - # consume blank lines - if {[regexp -line -- {\A([[:blank:]]*\n)} $rules_buf foo blanks]} { - set rules_buf [string range $rules_buf [string length $blanks] end] - incr ::line_count - continue - } - # extract left hand side - if {[regexp -line -- {\A\s*(\w+)\s*:} $rules_buf foo lhs]} { - add_token $lhs $::NONTERMINAL 0 0 nonassoc - set prev_lhs $lhs - } elseif {[regexp -line -- {\A\s*\|} $rules_buf foo]} { - if {$prev_lhs == ""} { - taccle_error "No previously declared left hand side" $::SYNTAX_ERROR - } - set lhs $prev_lhs - } elseif {[regexp -line -- {\A\s*\Z} $rules_buf]} { - # only whitespace left - break - } else { - taccle_error "No left hand side found" $::SYNTAX_ERROR - } - set rules_buf [string range $rules_buf [string length $foo] end] - - # read the rule derivation, which is everything up to a bar or - # semicolon - set rhs "" - set action "" - set done_deriv 0 - set num_lines 0 - while {$rules_buf != "" && $done_deriv != 1} { - switch -- [string index $rules_buf 0] { - | { set done_deriv 1 } - ; { - set done_deriv 1 - set prev_lhs "" - set rules_buf [string range $rules_buf 1 end] - } - "\n" { - incr num_lines - append rhs " " - set rules_buf [string range $rules_buf 1 end] - } - ' { - append rhs [string range $rules_buf 0 2] - set rules_buf [string range $rules_buf 3 end] - } - \{ { - # keep scanning until end of action found - set a "" - set rp 1 - set found_end 0 - while {!$found_end && $rp < [string length $rules_buf]} { - set c [string index $rules_buf $rp] - if {$c == "\}"} { - if {[info complete $a]} { - set found_end 1 - } else { - append a "\}" - } - } elseif {$c == "\n"} { - append a $c - incr num_lines - } else { - append a $c - } - incr rp - } - if {!$found_end} { - taccle_error "Unmatched `\{'" $::SYNTAX_ERROR - } - set action $a - set rules_buf [string range $rules_buf $rp end] - } - default { - set c [string index $rules_buf 0] - if {$action != "" && ![string is space $c]} { - # embedded action found; add a special rule for it - set pseudo_name "@PSEUDO$pseudo_count" - add_token $pseudo_name $::NONTERMINAL 0 0 nonassoc - set ::rule_table($::rule_count,l) $pseudo_name - set ::rule_table($::rule_count,d) "" - set ::rule_table($::rule_count,dc) 0 - set ::rule_table($::rule_count,a) $action - set ::rule_table($::rule_count,e) 0 - set ::rule_table($::rule_count,line) $::line_count - append rhs "$pseudo_name " - set action "" - incr pseudo_count - incr ::rule_count - } else { - append rhs $c - set rules_buf [string range $rules_buf 1 end] - } - } - } - } - if {$rules_buf == "" && $done_deriv == 0} { - taccle_error "Rule does not terminate" $::SYNTAX_ERROR - } - set derivation [string trim $rhs] - set deriv_list "" - set deriv_count 0 - set prec_next 0 - foreach token [split $derivation] { - if {$prec_next} { - # check that argument to %prec is a terminal symbol - if {![info exists ::token_table($token)] || \ - $::token_table($token,t) != $::TERMINAL} { - taccle_error "Argument to %prec is not a terminal symbol" $::GRAMMAR_ERROR - } - set ::rule_table($::rule_count,prec) $::token_table($token) - set prec_next 0 - continue - } - if {$token == "%prec"} { - set prec_next 1 - continue - } - if {[regexp -- {\A\'(.)\'\Z} $token foo c]} { - add_token $c $::TERMINAL 1 0 nonassoc - set token $c - } - if {$token != ""} { - if {[string range $token 0 6] == "@PSEUDO"} { - set ::rule_table([expr {$::rule_count - 1}],e) $deriv_count - } - - lappend deriv_list $token - incr deriv_count - } - } - if {$prec_next} { - taccle_error "%prec modifier has no associated terminal symbol" $::PARAM_ERROR - } - incr ::line_count $num_lines - set ::rule_table($::rule_count,l) $lhs - set ::rule_table($::rule_count,d) $deriv_list - set ::rule_table($::rule_count,dc) [llength $deriv_list] - set ::rule_table($::rule_count,a) $action - set ::rule_table($::rule_count,line) $::line_count - incr ::rule_count - } -} - -# Post-process the grammar by augmenting it and and replacing all -# tokens with their id values. -proc rewrite_grammar {} { - set ::rule_table(0,l) "start'" - if {[info exists ::start_symbol]} { - if {![info exists ::token_table($::start_symbol)]} { - taccle_error "Token given by %start does not exist" $::PARAM_ERROR - } - if {$::token_table($::start_symbol,t) == $::TERMINAL} { - taccle_error "Token given by %start is a terminal." $::PARAM_ERROR - } - set ::rule_table(0,d) $::start_symbol - } else { - set ::rule_table(0,d) $::rule_table(1,l) - } - set ::rule_table(0,dc) 1 - set ::rule_table(0,prec) 0 - set ::start_token_id [add_token "start'" $::NONTERMINAL 0 0 nonassoc] - set ::token_list [lsort -command tokid_compare $::token_list] - - # now go through grammar and replace all token names with their id - # number - for {set i 0} {$i < $::rule_count} {incr i} { - set ::rule_table($i,l) $::token_table($::rule_table($i,l)) - set new_deriv_list "" - foreach deriv $::rule_table($i,d) { - if {![info exists ::token_table($deriv)]} { - taccle_error "Symbol $deriv used, but is not defined as a token and has no rules." $::GRAMMAR_ERROR - } - lappend new_deriv_list $::token_table($deriv) - } - set ::rule_table($i,d) $new_deriv_list - # set the rule's precedence only if it was not already specified - if {![info exist ::rule_table($i,prec)]} { - set ::rule_table($i,prec) [get_prec $new_deriv_list] - } - } - - # check for unused tokens - set used_list [concat "error" [recurse_dfs $::start_token_id ""]] - foreach tok_id $::token_list { - if {[lsearch -exact $used_list $tok_id] == -1} { - taccle_warn "Token $::token_id_table($tok_id) unused." - } else { - lappend ::used_token_list $tok_id - } - } - # add to the used token list {$} but /not/ start' - set ::used_token_list [concat [lrange $::used_token_list 0 end-1] \ - $::token_table("\$")] -} - -# Determine which non-terminals are nullable. Any terminal which can -# be simplified to just an epsilon transition is nullable. -proc generate_nullable_table {} { - set nullable_found 1 - while {$nullable_found} { - set nullable_found 0 - foreach tok_id $::token_list { - if {[info exist ::nullable_table($tok_id)]} { - continue - } - if {$::token_id_table($tok_id,t) == $::TERMINAL} { - set ::nullable_table($tok_id) 0 - continue - } - for {set i 0} {$i < $::rule_count} {incr i} { - set lhs $::rule_table($i,l) - if {$lhs != $tok_id} { - continue - } - set rhs [lindex $::rule_table($i,d) 0] - if {$rhs == ""} { - set ::nullable_table($lhs) 1 - set nullable_found 1 - } else { - set nullable 0 - foreach r $rhs { - if {[info exists ::nullable_table($r)]} { - set nullable $::nullable_table($r) - break - } - } - if {$nullable} { - set ::nullable_table($lhs) 1 - set nullable_found 1 - } - } - } - } - } - foreach tok_id $::token_list { - if {![info exist ::nullable_table($tok_id)]} { - set ::nullable_table($tok_id) 0 - } - } -} - -# Generate the table of FIRST symbols for the grammar. -proc generate_first_table {} { - foreach tok_id $::token_list { - generate_first_recurse $tok_id "" - } -} - -# Recursively calculates the FIRST set for a given token, handling -# nullable terminals as well. -# -# @param tok_id id of token to generate FIRST set -# @param history list of tokens already examined -# @return list of tokens (including -1 for epsilon) in tok_id's FIRST set -proc generate_first_recurse {tok_id history} { - if {[lsearch -exact $history $tok_id] >= 0} { - return "" - } - if {[info exists ::first_table($tok_id)]} { - return $::first_table($tok_id) - } - if {$::token_id_table($tok_id,t) == $::TERMINAL} { - set ::first_table($tok_id) $tok_id - return $tok_id - } - # FIRST = union of all first non-terminals on rhs. if a - # non-terminal is nullable, then add FIRST of the following - # terminal to the FIRST set. keep repeating while nullable. - set first_union "" - for {set i 0} {$i < $::rule_count} {incr i} { - set lhs $::rule_table($i,l) - if {$lhs != $tok_id} { - continue - } - if {$::rule_table($i,dc) == 0} { - # empty rule, so add the special epsilon marker -1 to the FIRST set - lappend first_union -1 - } else { - foreach r $::rule_table($i,d) { - lconcat first_union [generate_first_recurse $r [concat $history $tok_id]] - if {$::nullable_table($r) == 0} { - break - } - } - } - } - set ::first_table($tok_id) [lsort -increasing -unique $first_union] - return $first_union -} - -# Generate the table of FOLLOW symbols for the grammar. -proc generate_follow_table {} { - set ::follow_table($::token_table(start')) $::token_table("\$") - foreach tok_id $::token_list { - generate_follow_recurse $tok_id "" - } -} - -# Recursively calculates the FOLLOW set for a given token, handling -# nullable terminals as well. -# -# @param tok_id id of token to generate FOLLOW set -# @param history list of tokens already examined -# @return list of tokens in tok_id's FOLLOW set -proc generate_follow_recurse {tok_id history} { - if {[lsearch -exact $history $tok_id] >= 0} { - return "" - } - if {[info exists ::follow_table($tok_id)]} { - return $::follow_table($tok_id) - } - set follow_union "" - for {set i 0} {$i < $::rule_count} {incr i} { - # if the token is on the rhs of the rule then FOLLOW includes - # the FIRST of the token following it; if at end of rule (or - # can be derived to end of rule) then FOLLOW includes the - # FOLLOW of the lhs - set rhs $::rule_table($i,d) - for {set j [expr {$::rule_table($i,dc) - 1}]} {$j >= 0} {incr j -1} { - set r [lindex $rhs $j] - if {$r != $tok_id} { - continue - } - set k [expr {$j + 1}] - set gamma [lindex $rhs $k] - if {$gamma != ""} { - lconcat follow_union [all_but_eps $::first_table($gamma)] - } - set at_end_of_list 1 - while {$k < $::rule_table($i,dc)} { - if {![has_eps $::first_table([lindex $rhs $k])]} { - set at_end_of_list 0 - break - } - incr k - } - if {$at_end_of_list} { - set lhs $::rule_table($i,l) - lconcat follow_union [generate_follow_recurse $lhs [concat $history $tok_id]] - } - } - } - set ::follow_table($tok_id) [lsort -increasing -unique $follow_union] - return $follow_union -} - -# Construct a canonical LR(1) by taking the start rule (rule 0) and -# successively adding closures/states until no more new states. -proc generate_lr1 {} { - # first add start rule to the closure list - set first_item [list [list 0 $::token_table("\$") 0]] - set first_closure [add_closure $first_item 0 1] - set ::lr1_table(0) [concat $first_item $first_closure] - - # used to keep count of total number of states produced by LR(1) - set ::next_lr1_state 1 - - # keep generating items until none remain - for {set state_pointer 0} {$state_pointer < $::next_lr1_state} {incr state_pointer} { - # iterate through each token, adding transitions to new state(s) - set trans_list "" - set oldclosure_list $::lr1_table($state_pointer) - foreach tok_id $::token_list { - set todo_list "" - set working_list "" - foreach item $oldclosure_list { - foreach {rule lookahead position} $item {} - if {$position >= $::rule_table($rule,dc)} { - # at end of rule; don't expand (and remove it - # from the list) - continue - } - set nexttoken [lindex $::rule_table($rule,d) $position] - if {$nexttoken == $tok_id} { - # item's next token matches the one currently - # saught; add it to the working list - lappend working_list $item - } else { - # item was not used yet -- add it back to the - # todo list - lappend todo_list $item - } - } - set oldclosure_list $todo_list - if {$working_list != ""} { - set new_closure "" - foreach item $working_list { - # move pointer ahead to the next position - foreach {rule lookahead position} $item {} - incr position - set newitem [list $rule $lookahead $position] - lappend new_closure $newitem - } - set new_closure [concat $new_closure \ - [add_closure $new_closure 0 [llength $working_list]]] - # add a transition out of this state -- to a - # previously examined state if possible, or else - # create a new state with my new closure - set next_state -1 - for {set i 0} {$i < $::next_lr1_state} {incr i} { - if {[lsort $::lr1_table($i)] == [lsort $new_closure]} { - set next_state $i - break - } - } - if {$next_state == -1} { - # create a new state - set ::lr1_table($::next_lr1_state) $new_closure - lappend trans_list [list $tok_id $::next_lr1_state] - incr ::next_lr1_state - } else { - # reuse existing state - lappend trans_list [list $tok_id $next_state] - } - - } - } - set ::lr1_table($state_pointer,trans) [lsort -command tokid_compare -index 0 $trans_list] - } -} - -# Successively add closures from LR(1) table to LALR(1) table merging -# kernels with similar cores. -proc generate_lalr1 {} { - for {set i 0} {$i < $::next_lr1_state} {incr i} { - # as matching closures are found change their mapping here - set state_mapping_table($i) $i - } - # go through all elements of LR(1) table and generate their cores. - # this will make future comparisons easier. - for {set i 0} {$i < $::next_lr1_state} {incr i} { - set core "" - foreach item $::lr1_table($i) { - lappend core [list [lindex $item 0] [lindex $item 2]] - } - set core_table($i) [lsort $core] - } - lappend new_lalr_states(0) 0 - for {set i 1} {$i < $::next_lr1_state} {incr i} { - set found_matching 0 - for {set j 0} {$j < $i} {incr j} { - if {$core_table($i) == $core_table($j)} { - # found a matching core -- change its mapping - set state_mapping_table($i) $state_mapping_table($j) - # because this state is being eliminated, shuffle all - # future states down one - for {set k [expr {$i + 1}]} {$k < $::next_lr1_state} {incr k} { - incr state_mapping_table($k) -1 - } - # merge state $i into state $j - lappend new_lalr_states($j) $i - set found_matching 1 - break - } - } - if {!$found_matching} { - lappend new_lalr_states($i) $i - } - } - # now copy items from LR(1) table to LALR(1) table - set ::next_lalr1_state 0 - for {set i 0} {$i < $::next_lr1_state} {incr i} { - if {![info exists new_lalr_states($i)]} { - # state no longer exists (it got merged into another one) - continue - } - # first merge together all lookaheads - set ::lalr1_table($::next_lalr1_state) $::lr1_table([lindex $new_lalr_states($i) 0]) - foreach state [lrange $new_lalr_states($i) 1 end] { - set ::lalr1_table($::next_lalr1_state) \ - [merge_closures $::lalr1_table($::next_lalr1_state) $::lr1_table($state)] - } - # now rewrite the transition table - foreach trans $::lr1_table($i,trans) { - foreach {symbol new_state} $trans {} - lappend ::lalr1_table($::next_lalr1_state,trans) \ - [list $symbol $state_mapping_table($new_state)] - } - incr ::next_lalr1_state - } -} - -# Takes the LALR(1) table and resolves precedence issues by removing -# transitions whenever the precedence values indicate a reduce instead -# of a shift. -proc resolve_precedences {} { - for {set i 0} {$i < $::next_lalr1_state} {incr i} { - # scan through all kernel items that are at the end of their - # rule. for those, use the precedence table to decide to keep - # a transition (a shift) or not (a reduce) - foreach item $::lalr1_table($i) { - foreach {rule lookahead position} $item {} - if {$position < $::rule_table($rule,dc) || \ - ![info exist ::lalr1_table($i,trans)]} { - continue - } - set rule_prec_tok $::rule_table($rule,prec) - set rule_prec_level $::prec_table($rule_prec_tok) - set rule_prec_dir $::prec_table($rule_prec_tok,dir) - set new_trans "" - foreach trans $::lalr1_table($i,trans) { - set trans_tok [lindex $trans 0] - if {[lsearch $lookahead $trans_tok] == -1} { - lappend new_trans $trans - continue - } - set trans_tok_level $::prec_table($trans_tok) - set trans_tok_dir $::prec_table($trans_tok,dir) - if {$rule_prec_dir == "nonassoc" || \ - $trans_tok_dir == "nonassoc" || \ - $rule_prec_level < $trans_tok_level || \ - ($rule_prec_level == $trans_tok_level && $rule_prec_dir == "right")} { - # precedence says to shift, so keep this transition - lappend new_trans $trans - } else { - taccle_warn "Conflict in state $i between rule $rule and token \"$trans_tok\", resolved as reduce." - } - } - set ::lalr1_table($i,trans) $new_trans - } - } -} - -# Check if the grammar contains any infinite recursions. -proc check_recursions {} { - set cleared "" - for {set i 0} {$i < $::next_lalr1_state} {incr i} { - if {[lsearch -exact $cleared $i] >= 0} { - continue - } - set cleared [get_cleared $i {} $cleared] - } -} - -# Recursively performs a DFS search through the LALR(1) table to check -# for cycles. In each node check if the position is at the end of any -# rule; this marks the node is "reducible" and it is added to the -# 'cleared' list. Otherwise recurse on each terminal transitioning -# out of this state. If a state and all of its transitions are not -# reducible then abort with an error. -# -# @param state which state within the LALR(1) table to examine -# @param history a list of states so far examined on this pass -# @param cleared a list of states which have already been verified as reducible -# -# @return a new cleared list, or an empty list of this state is not reducible -proc get_cleared {state history cleared} { - if {[lsearch -exact $cleared $state] >= 0} { - return $cleared - } - if {[lsearch -exact $history $state] >= 0} { - return {} - } - # check if any items in this closure are reducible; if so then - # this state passes - set token -1 - foreach item $::lalr1_table($state) { - foreach {rule lookahead position} $item {} - if {$position == $::rule_table($rule,dc)} { - return [concat $cleared $state] - } - if {$position == 0} { - set token $::rule_table($rule,l) - } - } - # recursively check all terminals transitioning out of this state; - # if none of the new states eventually reduce then report this as - # a cycle - foreach trans $::lalr1_table($state,trans) { - foreach {tok_id nextstate} $trans {} - if {$::token_id_table($tok_id,t) == $::TERMINAL} { - set retval [get_cleared $nextstate [concat $history $state] $cleared] - if {[llength $retval] > 0} { - return [concat $retval $state] - } - } - } - if {$token == -1} { - puts stderr "OOPS: should not have gotten here!" - exit -1 - } - set ::line_count $::rule_table($rule,line) - taccle_error "Token $::token_id_table($token) appears to recurse infinitely" $::GRAMMAR_ERROR -} - -# Takes the LALR(1) table and generates the LALR(1) transition table. -# For terminals do a shift to the new state. For non-terminals reduce -# when the next token is a lookahead. Detect shift/reduce conflicts; -# resolve by giving precedence to shifting. Detect reduce/reduce -# conflicts and resolve by reducing to the first rule found. -proc generate_lalr1_parse_table {} { - for {set i 0} {$i < $::next_lalr1_state} {incr i} { - foreach item $::lalr1_table($i) { - foreach {rule lookahead position} $item {} - if {$position >= $::rule_table($rule,dc)} { - if {$rule == 0} { - set command "accept" - } else { - set command "reduce" - } - set token_list $lookahead - # target for a reduce/accept is which rule to use - # while accepting - set target $rule - } else { - set token [lindex $::rule_table($rule,d) $position] - if {$::token_id_table($token,t) == $::TERMINAL} { - set command "shift" - } else { - set command "goto" - } - set token_list [list $token] - # target for a shift/goto is the new state to move to - set target "" - foreach trans $::lalr1_table($i,trans) { - foreach {tok_id nextstate} $trans {} - if {$tok_id == $token} { - set target $nextstate - break - } - } - # this token must have been consumed by shift/reduce - # conflict resolution through the precedence table - # (above) - if {$target == ""} { - continue - } - } - - foreach token $token_list { - # check for shift/reduce conflicts - if {[info exists ::lalr1_parse($i:$token)] && \ - $::lalr1_parse($i:$token) != $command} { - # shifting takes precedence, so overwrite table - # entry if needed - if {$::lalr1_parse($i:$token) == "shift"} { - taccle_warn "Shift/Reduce error in state $i, token \"$::token_id_table($token)\", resolved by keeping shift." - break - } - taccle_warn "Shift/Reduce error in state $i between rule $::lalr1_parse($i:$token,target) and token \"$::token_id_table($token)\", resolved as shift." - unset ::lalr1_parse($i:$token,target) - } - set ::lalr1_parse($i:$token) $command - # check for reduce/reduce conflicts - # (theoretically it is impossible to have a shift/shift error) - if {[info exists ::lalr1_parse($i:$token,target)] && \ - $::lalr1_parse($i:$token,target) != $target} { - taccle_warn "Reduce/Reduce error in state $i, token \"$::token_id_table($token)\", resolved by reduce to rule $::lalr1_parse($i:$token,target)." - break - } - set ::lalr1_parse($i:$token,target) $target - } - - } - } -} - -###################################################################### -# utility routines that actually handle writing parser to output files - -# Writes to the destination file utility functions called by yyparse -# as well as by user-supplied actions. -proc write_parser_utils {} { - puts $::dest " -###### -# Begin autogenerated taccle (version $::TACCLE_VERSION) routines. -# Although taccle itself is protected by the GNU Public License (GPL) -# all user-supplied functions are protected by their respective -# author's license. See http://mini.net/tcl/taccle for other details. -###### - -namespace eval ${::p} \{ - variable yylval {} - variable table - variable rules - variable token {} - variable yycnt 0 - variable yyerr 0 - variable save_state 0 - - namespace export yylex -\} - -proc ${::p}::YYABORT \{\} \{ - return -code return 1 -\} - -proc ${::p}::YYACCEPT \{\} \{ - return -code return 0 -\} - -proc ${::p}::YYERROR \{\} \{ - variable yyerr - set yyerr 1 -\} - -proc ${::p}::yyclearin \{\} \{ - variable token - variable yycnt - set token {} - incr yycnt -1 -\} - -proc ${::p}::yyerror \{s\} \{ - puts stderr \$s -\} - -proc ${::p}::setupvalues \{stack pointer numsyms\} \{ - upvar 1 1 y - set y \{\} - for \{set i 1\} \{\$i <= \$numsyms\} \{incr i\} \{ - upvar 1 \$i y - set y \[lindex \$stack \$pointer\] - incr pointer - \} -\} - -proc ${::p}::unsetupvalues \{numsyms\} \{ - for \{set i 1\} \{\$i <= \$numsyms\} \{incr i\} \{ - upvar 1 \$i y - unset y - \} -\}" -} - -# Writes to the destination file the actual parser including LALR(1) -# table. -proc write_parser {} { - write_array $::dest ${::p}::table [array get ::lalr1_parse] - write_array $::dest ${::p}::rules [array get ::rule_table *l] - write_array $::dest ${::p}::rules [array get ::rule_table *dc] - write_array $::dest ${::p}::rules [array get ::rule_table *e] - if {$::parse_error} { - write_array $::dest ${::p}::lr1_table [array get ::lr1_table] - write_array $::dest ${::p}::token_id_table [array get ::token_id_table] - } - - puts $::dest "\nproc ${::p}::yyparse {} { - variable yylval - variable table - variable rules - variable token - variable yycnt - variable lr1_table - variable token_id_table - variable yyerr - variable save_state - - set yycnt 0 - set state_stack {0} - set value_stack {{}} - set token \"\" - set accepted 0 - set yyerr 0 - set save_state 0 - - while {\$accepted == 0} { - set state \[lindex \$state_stack end\] - if {\$token == \"\"} { - set yylval \"\" - set token \[yylex\] - set buflval \$yylval - if {\$token>0} { - incr yycnt - } - } - if {!\[info exists table(\$state:\$token)\] || \$yyerr} { - if {!\$yyerr} { - set save_state \$state - } - \# pop off states until error token accepted - while {\[llength \$state_stack\] > 0 && \\ - !\[info exists table(\$state:error)]} { - set state_stack \[lrange \$state_stack 0 end-1\] - set value_stack \[lrange \$value_stack 0 \\ - \[expr {\[llength \$state_stack\] - 1}\]\] - set state \[lindex \$state_stack end\] - } - if {\[llength \$state_stack\] == 0} {" - if {$::parse_error} { -puts $::dest " - set rr { } - if {\[info exists lr1_table(\$save_state,trans)\] && \[llength \$lr1_table(\$save_state,trans)\] >= 1} { - foreach trans \$lr1_table(\$save_state,trans) { - foreach {tok_id nextstate} \$trans { - set ss \$token_id_table(\$tok_id,title) - if {\$ss != {}} { - append rr \"\$ss, \" - } - } - } - } - set rr \[string trimleft \$rr { }\] - set rr \[string trimright \$rr {, }\] - yyerror \"parse error, expecting: \$rr\" -" - } else { -puts $::dest " - yyerror \"parse error\" -" - } -puts $::dest " - return 1 - } - lappend state_stack \[set state \$table(\$state:error,target)\] - lappend value_stack {} - \# consume tokens until it finds an acceptable one - while {!\[info exists table(\$state:\$token)]} { - if {\$token == 0} { - yyerror \"end of file while recovering from error\" - return 1 - } - set yylval {} - set token \[yylex\] - set buflval \$yylval - } - continue - } - switch -- \$table(\$state:\$token) { - shift { - lappend state_stack \$table(\$state:\$token,target) - lappend value_stack \$buflval - set token \"\" - } - reduce { - set rule \$table(\$state:\$token,target) - set ll \$rules(\$rule,l) - if \{\[info exists rules(\$rule,e)\]\} \{ - set dc \$rules(\$rule,e) - \} else \{ - set dc \$rules(\$rule,dc) - \} - set stackpointer \[expr {\[llength \$state_stack\]-\$dc}\] - setupvalues \$value_stack \$stackpointer \$dc - set _ \$1 - set yylval \[lindex \$value_stack end\] - switch -- \$rule {" - for {set i 0} {$i < $::rule_count} {incr i} { - if {[info exists ::rule_table($i,a)] && [string trim $::rule_table($i,a)] != ""} { - puts $::dest " $i { $::rule_table($i,a) }" - } - } - - puts $::dest " } - unsetupvalues \$dc - # pop off tokens from the stack if normal rule - if \{!\[info exists rules(\$rule,e)\]\} \{ - incr stackpointer -1 - set state_stack \[lrange \$state_stack 0 \$stackpointer\] - set value_stack \[lrange \$value_stack 0 \$stackpointer\] - \} - # now do the goto transition - lappend state_stack \$table(\[lindex \$state_stack end\]:\$ll,target) - lappend value_stack \$_ - } - accept { - set accepted 1 - } - goto - - default { - puts stderr \"Internal parser error: illegal command \$table(\$state:\$token)\" - return 2 - } - } - } - return 0 -} - -###### -# end autogenerated taccle functions -###### -" -} - -# Pretty-prints an array to a file descriptor. Code contributed by -# jcw. -# -# @param fd file descriptor to which write the array -# @param name name of array to declare within the file -# @param values list of 2-ple values -proc write_array {fd name values} { - puts $fd "\narray set $name {" - foreach {x y} $values { - puts $fd " [list $x $y]" - } - puts $fd "}" -} - -# Writes a header file that should be [source]d by the lexer. -proc write_header_file {} { - # scan through token_table and write out all non-implicit terminals - foreach tok_id $::token_list { - if {$::token_id_table($tok_id,t) == $::TERMINAL && \ - [string is integer $tok_id] && $tok_id >= 256} { - set token $::token_id_table($tok_id) - puts $::header "set ${token} $tok_id" - } - } -} - -###################################################################### -# utility functions - -# Adds a token to the token table, checking that it does not already -# exist. Returns the ID for the token (either old one if token -# already exists or the newly assigned id value). -# -# @param token_name name of token to add -# @param type type of token, either $::TERMINAL or $::NON_TERMINAL -# @param implicit for $::TERMINAL tokens, 1 if the token is implicitly -# declared -# @param prec_level precedence level for token -# @param prec_dir direction of precedence, either <var>left</var>, -# <var>right</var>, or <var>nonassoc</var> -# @return id value for this token -proc add_token {token_name type implicit prec_level prec_dir {token_title {}}} { - if {$token_name == "\$"} { - taccle_error "The token '$' is reserved and may not be used in productions." $::SYNTAX_ERROR - } - if {$token_name == "\{" || $token_name == 0} { - taccle_error "Literal value $token_name not allowed; define a %token instead" $::SYNTAX_ERROR - } - if [info exists ::token_table($token_name)] { - set id $::token_table($token_name) - if {$::token_table($token_name,t) == $type} { - # token already exists; modify its precedence level if necessary - if {$::prec_table($id) < $prec_level} { - taccle_warn "Redefining precedence of $token_name" - set ::prec_table($id) $prec_level - set ::prec_table($id,dir) $prec_dir - } - set ::token_id_table($id,line) $::line_count - return $id - } - set old_type [expr {$::token_table($token_name,t) == 1 ? "non-" : ""}]terminal - taccle_error "Token $token_name already declared as a $old_type" $::GRAMMAR_ERROR - } - if $implicit { - set ::token_table($token_name) $token_name - set id $token_name - } else { - set ::token_table($token_name) $::next_token_id - set id $::next_token_id - incr ::next_token_id - } - set ::token_table($token_name,t) $type - set ::token_id_table($id) $token_name - set ::token_id_table($id,title) $token_title - set ::token_id_table($id,t) $type - set ::token_id_table($id,line) $::line_count - lappend ::token_list $id - set ::prec_table($id) $prec_level - set ::prec_table($id,dir) $prec_dir - return $id -} - -# Adds closures to each item on $closure_list, starting from the index -# $closure_pointer. Keeps adding closures until no more are added. -# -# @param closure_list list of closures to process -# @param closure_pointer index into $closure_list to which start -# @param original_length original size of $closure_list -# @return list of closures added -proc add_closure {closure_list closure_pointer original_length} { - set orig_closure_pointer [expr {$closure_pointer + $original_length}] - # keep adding items to the closure list until no more - while {$closure_pointer < [llength $closure_list]} { - set item [lindex $closure_list $closure_pointer] - incr closure_pointer - foreach {rule lookahead position} $item {} - set mylength $::rule_table($rule,dc) - if {$position < $mylength} { - set nexttoken [lindex $::rule_table($rule,d) $position] - if {$::token_id_table($nexttoken,t) == $::TERMINAL} { - continue - } - # the lookahead is the FIRST of the rule /after/ - # nexttoken, or the current lookahead if at the end of - # rule. if the next token is NULLABLE then the lookahead - # includes that which FOLLOWS it - set beta_pos [expr {$position + 1}] - if {$beta_pos >= $mylength} { - set nextfirst $lookahead - } else { - set n [lindex $::rule_table($rule,d) $beta_pos] - set nextfirst [all_but_eps $::first_table($n)] - if {$::nullable_table($n)} { - set nextfirst [lsort -unique [concat $nextfirst $::follow_table($n)]] - } - } - for {set rule_num 0} {$rule_num < $::rule_count} {incr rule_num} { - if {$::rule_table($rule_num,l) != $nexttoken} { - continue - } - set newitem [list $rule_num $nextfirst 0] - set closure_list [merge_closures $closure_list [list $newitem]] - } - } - } - return [lrange $closure_list $orig_closure_pointer end] -} - -# Recurses through all productions, recording which tokens are -# actually used by the grammar. Tokens used to indicate a rule's -# precedence are also added. Returns a list of tokens used; note that -# this list can (and probably will) include duplicates. -# -# @param tok_id id of token to start -# @param history list of tok_id's already examined -# @return list of tokens used -proc recurse_dfs {tok_id history} { - if {[lsearch -exact $history $tok_id] >= 0} { - return $history - } - if {$::token_id_table($tok_id,t) == $::TERMINAL} { - return [concat $history $tok_id] - } - lappend history $tok_id - for {set i 0} {$i < $::rule_count} {incr i} { - set lhs $::rule_table($i,l) - if {$lhs == $tok_id} { - foreach deriv $::rule_table($i,d) { - set history [recurse_dfs $deriv $history] - } - lconcat history $::rule_table($i,prec) - } - } - return $history -} - -# Given a line, returns a new line with any comments removed. -# -# @param line string with a possible comment -# @return line with any commens removed -proc strip_comments {line} { - regexp -- {\A([^\#]*)} $line foo line - return $line -} - -# Combines unique elements of the two closures, also merging lookahead -# symbols, and returns the new closure. -# -# @param closure1 first closure to merge -# @param closure2 second closure to merge -# @return $closure1 and $closure2 merged together, with duplicated removed -proc merge_closures {closure1 closure2} { - foreach item2 $closure2 { - foreach {rule2 lookahead2 pos2} $item2 {} - set found_match 0 - for {set i 0} {$i < [llength $closure1]} {incr i} { - foreach {rule1 lookahead1 pos1} [lindex $closure1 $i] {} - if {$rule2 == $rule1 && $pos2 == $pos1} { - set lookahead1 [lsort -uniq [concat $lookahead1 $lookahead2]] - lset closure1 $i [list $rule1 $lookahead1 $pos1] - set found_match 1 - break - } - } - if {!$found_match} { - lappend closure1 $item2 - } - } - return $closure1 -} - -# Compares two token id values. If the two are integers then uses -# their values for comparison; otherwise performs a string comparison. -# Integer values are always "greater than" strings. -# -# @param a first token id -# @param b second token id -# @return -1 if <var>a</var> is less than <var>b</var>, 1 if -# <var>a</var> is greater, otherwise 0 -proc tokid_compare {a b} { - if {[string is integer $a] && [string is integer $b]} { - if {$a < $b} { - return -1 - } else { - return 1 - } - } - if [string is integer $a] { - return 1 - } - if [string is integer $b] { - return -1 - } - return [string compare $a $b] -} - -# Given a list, returns all everything in it except for any elements -# of value "-1", which corresponds with the epsilon symbol. -# -# @param first_list list of tokens (presumably a FIRST set) -# @return new list with all -1 values removed -proc all_but_eps {first_list} { - set new_list "" - foreach tok $first_list { - if {$tok != -1} { - lappend new_list $tok - } - } - return $new_list -} - -# Returns truth if the element value "-1", corresponding with the -# epsilon symbol, resides within the first list $first_list. -# -# @param first_list list of tokens (presumably a FIRST set) -# @return 1 if $first_list has the element -1, 0 otherwise -proc has_eps {first_list} { - foreach tok $first_list { - if {$tok == -1} { - return 1 - } - } - return 0 -} - -# Given a list of tokens, returns the token with highest precedence -# level. -# -# @param tok_list list of token ids -# @return token with highest precedence; in case of tie returns first -# one found -proc get_prec {tok_list} { - set prec_token 0 - foreach tok $tok_list { - if {$::prec_table($tok) > $::prec_table($prec_token)} { - set prec_token $tok - } - } - return $prec_token -} - -# Appends the first list a flattened version of the second, but only -# if the second is non-empty. -# -# @param list first list -# @param lists list of lists to append -# @return new list -proc lconcat {list lists} { - upvar $list l - if {$lists != ""} { - set l [concat $l $lists] - } else { - return $l - } -} - -# Retrives a parameter from the options list. If no parameter exists -# then abort with an error very reminisicent of C's -# <code>getopt</code> function; otherwise increment -# <code>param_num</code> by one. -# -# @param param_list list of parameters from the command line -# @param param_num index into <code>param_list</code> to retrieve -# @param param_name name of the parameter, used when reporting an error -# @return the <code>$param_num</code>'th element into <code>$param_list</code> -proc get_param {param_list param_num param_name} { - upvar $param_num pn - incr pn - if {$pn >= [llength $param_list]} { - puts stderr "taccle: option requires an argument -- $param_name" - exit $::PARAM_ERROR - } - return [lindex $param_list $pn] -} - -# Display to standard error a message, then abort the program. -proc taccle_error {message returnvalue} { - if {$::verbose != ""} { - puts $::verbose "$message (line $::line_count)" - } - puts stderr "$message (line $::line_count)" - exit $returnvalue -} - -# Display a message to standard error if warnings enabled. Write to -# the verbose output file if verbose is enabled. -proc taccle_warn {message} { - if {$::show_warnings} { - puts stderr $message - } - if {$::verbose != ""} { - puts $::verbose "$message" - } -} - -# Print to a particular channel a brief summary of taccle command line -# options. -proc print_taccle_help {chan} { - puts $chan "taccle: a Tcl compiler compiler -Usage: taccle \[options\] file - file a taccle grammar specification file - -Options: - -h print this help message and quit - -d write extra output file containing Tcl code to be - \[source\]d by yylex - -o FILE specify name to write parser - -v write extra output file containing descriptions of all - parser states and extended information about conflicts - -w display all warnings to standard error - -p PREFIX change default yy prefix to PREFIX - --version print taccle version and quit - -For more information see http://mini.net/tcl/taccle" -} - -# Displays to standard out the taccle version, then exits program. -proc print_taccle_version {} { - puts "taccle version $::TACCLE_VERSION" - exit 0 -} - -###################################################################### -# internal debugging routines - -proc print_symbol_table {} { - puts $::verbose "token table:" - puts $::verbose [format "%-5s %-10s %s" "id" "token" "type"] - foreach tok_id $::token_list { - set token $::token_id_table($tok_id) - if {$::token_id_table($tok_id,t) == $::TERMINAL} { - set type "terminal" - } else { - set type "non-terminal" - } - puts $::verbose [format "%-5s %-10s %s" $tok_id $token $type] - } -} - -proc print_rule_table {} { - puts $::verbose "rule table:" - for {set i 0} {$i < $::rule_count} {incr i} { - set lhs $::token_id_table($::rule_table($i,l)) - set deriv_list "" - foreach deriv $::rule_table($i,d) { - lappend deriv_list $::token_id_table($deriv) - } - if {$deriv_list == ""} { - set deriv_list "\#\# empty \#\#" - } - puts $::verbose [format "%3d: %-10s -> %s" $i $lhs $deriv_list] - } -} - -proc print_first_table {} { - puts $::verbose "first table:" - foreach tok_id $::token_list { - if {$tok_id == -1} { - continue - } - set token $::token_id_table($tok_id) - set first_list "" - foreach first $::first_table($tok_id) { - if {$first >= 0} { - lappend first_list $::token_id_table($first) - } - } - puts $::verbose [format "%-10s => %s" $token $first_list] - } -} - -proc print_closure {closure_list indent dest} { - foreach item $closure_list { - foreach {rule lookahead position} $item {} - set lhs $::token_id_table($::rule_table($rule,l)) - set deriv_list "" - set i 0 - foreach deriv $::rule_table($rule,d) { - if {$i == $position} { - lappend deriv_list "." - } - lappend deriv_list $::token_id_table($deriv) - incr i - } - if {$position == $::rule_table($rule,dc)} { - lappend deriv_list "." - } - set lookahead_list "" - foreach la $lookahead { - lappend lookahead_list $::token_id_table($la) - } - puts $dest \ - [format "%*s %-10s -> %s, %s" $indent "" $lhs $deriv_list $lookahead_list] - } -} - -proc print_lr_table {table_name num_entries} { - upvar $table_name table - for {set i 0} {$i < $num_entries} {incr i} { - puts $::verbose "state $i:" - print_closure $table($i) 2 $::verbose - if {[info exists table($i,trans)] && [llength $table($i,trans)] >= 1} { - puts -nonewline $::verbose [format "%*s transitions:" 2 ""] - foreach trans $table($i,trans) { - foreach {tok_id nextstate} $trans {} - puts -nonewline $::verbose " $::token_id_table($tok_id) => s$nextstate" - } - puts $::verbose "" - } - puts $::verbose "" - } -} - -proc print_lr1_table {} { - puts $::verbose "lr(1) table:" - print_lr_table ::lr1_table $::next_lr1_state -} - -proc print_lalr1_table {} { - puts $::verbose "lalr(1) table:" - print_lr_table ::lalr1_table $::next_lalr1_state -} - -proc print_lalr1_parse {} { - puts $::verbose "generated lalr(1) parse table:" - puts -nonewline $::verbose "state " - foreach tok_id $::used_token_list { - set token [string range $::token_id_table($tok_id) 0 4] - puts -nonewline $::verbose [format " %-5s" $token] - } - puts $::verbose "" - for {set i 0} {$i < $::next_lalr1_state} {incr i} { - puts -nonewline $::verbose [format "%4s " $i] - foreach tok_id $::used_token_list { - if [info exists ::lalr1_parse($i:$tok_id)] { - switch -- $::lalr1_parse($i:$tok_id) { - shift { set s "sh" } - goto { set s "go" } - reduce { set s "re" } - accept { set s "accept" } - } - if {$s != "accept"} { - append s $::lalr1_parse($i:$tok_id,target) - } - puts -nonewline $::verbose [format " %-5s" $s] - } else { - puts -nonewline $::verbose " " - } - } - puts $::verbose "" - } -} - -###################################################################### -# other taccle functions - -# Parse the taccle command line. -proc taccle_args {argv} { - set argvp 0 - set write_defs_file 0 - set write_verbose_file 0 - set ::parse_error 0 - set out_filename "" - set ::p "yy" - set ::show_warnings 0 - while {$argvp < [llength $argv]} { - set arg [lindex $argv $argvp] - switch -- $arg { - "-d" { set write_defs_file 1 } - "-h" - - "--help" { print_taccle_help stdout; exit 0 } - "-o" { set out_filename [get_param $argv argvp "o"] } - "-v" - "--verbose" { set write_verbose_file 1 } - "-w" { set ::show_warnings 1 } - "-p" { - set prefix [get_param $argv argvp "p"] - set ::p [string tolower $prefix] - } - "--version" { print_taccle_version } - default { - if {[string index $arg 0] != "-"} { - break - } else { - puts stderr "taccle: unknown option $arg" - print_taccle_help stderr - exit $::PARAM_ERROR - } - } - } - incr argvp - } - if {$argvp >= [llength $argv]} { - puts stderr "taccle: no grammar file given" - print_taccle_help stderr - exit $::IO_ERROR - } - set ::in_filename [lindex $argv $argvp] - set ::in_dir [file dirname $::in_filename] - if {$out_filename == ""} { - set out_filename [file rootname $::in_filename] - append out_filename ".tcl" - } - if [catch {open $::in_filename r} ::src] { - puts stderr "Could not open grammar file '$::in_filename'." - exit $::IO_ERROR - } - if [catch {open $out_filename w} ::dest] { - puts stderr "Could not open output file '$out_filename'." - exit $::IO_ERROR - } - if $write_defs_file { - set header_filename "[file rootname $out_filename].tab.tcl" - if [catch {open $header_filename w} ::header] { - puts stderr "Could not open header file '$header_filename'." - exit $::IO_ERROR - } - } else { - set ::header "" - } - if $write_verbose_file { - set verbose_filename "[file rootname $out_filename].output" - if [catch {open $verbose_filename w} ::verbose] { - puts stderr "Could not open verbose file '$verbose_filename'." - exit $::IO_ERROR - } - } else { - set ::verbose "" - } -} - -# Actually do the parser generation. -proc taccle_main {} { - set ::line_count 0 - - # counts number of rules in the grammar - # rule number 0 is reserved for the special augmentation S' -> S - set ::rule_count 1 - - # used to keep track of token IDs: - # 0 is reserved for the special token '$' - # 256 for the error token - set ::next_token_id 257 - - # used to keep track of operator precedence level - # level 0 is reserved for terminals without any precedence - set ::next_precedence 1 - - # keep track of where within the file I am: - # definitions, rules, or subroutines - set file_state definitions - - while {[gets $::src line] >= 0} { - incr ::line_count - - if {$line == "%%"} { - if {$file_state == "definitions"} { - set file_state "rules" - } elseif {$file_state == "rules"} { - set file_state "subroutines" - } else { - taccle_error "Syntax error." $::SYNTAX_ERROR - } - } else { - if {$file_state == "definitions"} { - if {[lindex $line 0] == "#include"} { - set fn [lindex $line 1] - if {$fn != {}} { - if [catch {open [file join $::in_dir $fn] r} ch] { - puts stderr "Could not open definition file '$fn'." - exit $::IO_ERROR - } - while {[gets $ch line] >= 0} { - incr ::line_count - handle_defs $line - } - catch {close $fn} - } - } else { - handle_defs $line - } - } elseif {$file_state == "rules"} { - # keep reading the rest of the file until EOF or - # another '%%' appears - set rules_buf [strip_comments $line] - while {[gets $::src line] >= 0 && $file_state == "rules"} { - if {$line == "%%"} { - set file_state "subroutines" - } elseif {[lindex $line 0] == "#include"} { - set fn [lindex $line 1] - if {$fn != {}} { - if [catch {open [file join $::in_dir $fn] r} ch] { - puts stderr "Could not open include file '$fn'." - exit $::IO_ERROR - } - while {[gets $ch line] >= 0} { - incr ::line_count - append rules_buf "\n" [strip_comments $line] - } - catch {close $fn} - } - } else { - append rules_buf "\n" [strip_comments $line] - } - } - build_parser $rules_buf - set file_state "subroutines" - write_parser_utils - write_parser - } else { - # file_state is subroutines -- copy verbatim to output file - puts $::dest $line - } - } - } - if {$::header != ""} { - write_header_file - } - if {$::verbose != ""} { - print_symbol_table - puts $::verbose "" - print_rule_table - puts $::verbose "" - #print_first_table - #puts $::verbose "" - #print_lr1_table - print_lalr1_table - print_lalr1_parse - } -} - -###################################################################### -# start of actual script - -set IO_ERROR 1 -set SYNTAX_ERROR 2 -set PARAM_ERROR 3 -set GRAMMAR_ERROR 4 - -set TERMINAL 0 -set NONTERMINAL 1 - -taccle_args $argv -taccle_main |