backout parser changes

1 files changed, 0 insertions, 1607 deletions

diff --git a/taccle/taccle.tcl b/taccle/taccle.tcl
deleted file mode 100755
index 368d8ea..0000000
--- a/taccle/taccle.tcl
+++ /dev/null
@@ -1,1607 +0,0 @@
-#!/usr/bin/tclsh
-
-# $Id: taccle.tcl,v 1.6 2005/03/17 20:42:21 tang Exp $
-
-set TACCLE_VERSION 1.1
-
-#//#
-# 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" {
-                foreach token_name [split $args] {
-                    if {$token_name != ""} {
-                        # add the terminal token to the table
-                        add_token $token_name $::TERMINAL 0 0 nonassoc
-                    }
-                }
-            }
-            "%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 $args
-            }
-            default {
-                taccle_error "Unknown declaration \"$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.
-######
-
-proc ${::P}ABORT \{\} \{
-    return -code return 1
-\}
-
-proc ${::P}ACCEPT \{\} \{
-    return -code return 0
-\}
-
-proc ${::p}clearin \{\} \{
-    upvar ${::p}token t
-    set t \"\"
-\}
-
-proc ${::p}error \{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]
-    
-    puts $::dest "\nproc ${::p}parse {} {
-    set ${::p}state_stack {0}
-    set ${::p}value_stack {{}}
-    set ${::p}token \"\"
-    set ${::p}accepted 0
-    while {\$${::p}accepted == 0} {
-        set ${::p}state \[lindex \$${::p}state_stack end\]
-        if {\$${::p}token == \"\"} {
-            set ::${::p}lval \"\"
-            set ${::p}token \[${::p}lex\]
-            set ${::p}buflval \$::${::p}lval
-        }
-        if {!\[info exists ::${::p}table(\$${::p}state:\$${::p}token)\]} {
-            \# pop off states until error token accepted
-            while {\[llength \$${::p}state_stack\] > 0 && \\
-                       !\[info exists ::${::p}table(\$${::p}state:error)]} {
-                set ${::p}state_stack \[lrange $${::p}state_stack 0 end-1\]
-                set ${::p}value_stack \[lrange $${::p}value_stack 0 \\
-                                       \[expr {\[llength $${::p}state_stack\] - 1}\]\]
-                set ${::p}state \[lindex $${::p}state_stack end\]
-            }
-            if {\[llength \$${::p}state_stack\] == 0} {
-                ${::p}error \"parse error\"
-                return 1
-            }
-            lappend ${::p}state_stack \[set ${::p}state \$::${::p}table($${::p}state:error,target)\]
-            lappend ${::p}value_stack {}
-            \# consume tokens until it finds an acceptable one
-            while {!\[info exists ::${::p}table(\$${::p}state:\$${::p}token)]} {
-                if {\$${::p}token == 0} {
-                    ${::p}error \"end of file while recovering from error\"
-                    return 1
-                }
-                set ::${::p}lval {}
-                set ${::p}token \[${::p}lex\]
-                set ${::p}buflval \$::${::p}lval
-            }
-            continue
-        }
-        switch -- \$::${::p}table(\$${::p}state:\$${::p}token) {
-            shift {
-                lappend ${::p}state_stack \$::${::p}table(\$${::p}state:\$${::p}token,target)
-                lappend ${::p}value_stack \$${::p}buflval
-                set ${::p}token \"\"
-            }
-            reduce {
-                set ${::p}rule \$::${::p}table(\$${::p}state:\$${::p}token,target)
-                set ${::p}l \$::${::p}rules(\$${::p}rule,l)
-                if \{\[info exists ::${::p}rules(\$${::p}rule,e)\]\} \{
-                    set ${::p}dc \$::${::p}rules(\$${::p}rule,e)
-                \} else \{
-                    set ${::p}dc \$::${::p}rules(\$${::p}rule,dc)
-                \}
-                set ${::p}stackpointer \[expr {\[llength \$${::p}state_stack\]-\$${::p}dc}\]
-                ${::p}setupvalues \$${::p}value_stack \$${::p}stackpointer \$${::p}dc
-                set _ \$1
-                set ::${::p}lval \[lindex \$${::p}value_stack end\]
-                switch -- \$${::p}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 "                }
-                ${::p}unsetupvalues \$${::p}dc
-                # pop off tokens from the stack if normal rule
-                if \{!\[info exists ::${::p}rules(\$${::p}rule,e)\]\} \{
-                    incr ${::p}stackpointer -1
-                    set ${::p}state_stack \[lrange \$${::p}state_stack 0 \$${::p}stackpointer\]
-                    set ${::p}value_stack \[lrange \$${::p}value_stack 0 \$${::p}stackpointer\]
-                \}
-                # now do the goto transition
-                lappend ${::p}state_stack \$::${::p}table(\[lindex \$${::p}state_stack end\]:\$${::p}l,target)
-                lappend ${::p}value_stack \$_
-            }
-            accept {
-                set ${::p}accepted 1
-            }
-            goto -
-            default {
-                puts stderr \"Internal parser error: illegal command \$::${::p}table(\$${::p}state:\$${::p}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"
-        }
-    }
-    puts $::header "set ::${::p}lval \{\}"
-}
-
-######################################################################
-# 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 $::TERMINAL tokens, 1 if the token is implicitly
-# declared
-# @param prec_level precedence level for token
-# @param prec_dir direction of precedence, either <var>left</var>,
-# <var>right</var>, or <var>nonassoc</var>
-# @return id value for this token
-proc add_token {token_name type implicit prec_level prec_dir} {
-    if {$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,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 $::verbose ""
-    }
-}
-
-######################################################################
-# other taccle functions
-
-# Parse the taccle command line.
-proc taccle_args {argv} {
-    set argvp 0
-    set write_defs_file 0
-    set write_verbose_file 0
-    set out_filename ""
-    set ::p "yy"
-    set ::P "YY"
-    set ::show_warnings 0
-    while {$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]
-                set ::P [string toupper $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 $argvp]
-    if {$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"} {
-                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"
-                    } 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