diff options
Diffstat (limited to 'generic/tclCompExpr.c')
| -rw-r--r-- | generic/tclCompExpr.c | 83 |
1 files changed, 63 insertions, 20 deletions
diff --git a/generic/tclCompExpr.c b/generic/tclCompExpr.c index fb3d1f4..9028fa4 100644 --- a/generic/tclCompExpr.c +++ b/generic/tclCompExpr.c @@ -10,36 +10,77 @@ * See the file "license.terms" for information on usage and redistribution of * this file, and for a DISCLAIMER OF ALL WARRANTIES. * - * RCS: @(#) $Id: tclCompExpr.c,v 1.57 2007/07/03 18:37:00 dgp Exp $ + * RCS: @(#) $Id: tclCompExpr.c,v 1.58 2007/07/05 18:31:52 dgp Exp $ */ #include "tclInt.h" #include "tclCompile.h" /* CompileEnv */ /* - * Set of lexeme codes stored in OpNode structs to label and categorize the - * lexemes found. + * Set of lexeme codes returned by ParseLexeme(). + * + * First, each lexeme belongs to one of four categories, which determine + * its place in the parse tree. We use the two high bits of the + * (unsigned char) value to store a NODE_TYPE code. */ -#define LEAF (3<<6) -#define UNARY (2<<6) -#define BINARY (1<<6) - -#define NODE_TYPE ( LEAF | UNARY | BINARY) +#define NODE_TYPE 0xC0 -#define PLUS 1 -#define MINUS 2 -#define BAREWORD 3 -#define INCOMPLETE 4 -#define INVALID 5 +/* + * The four category values are LEAF, UNARY, and BINARY, explained below, + * and "uncategorized", which is used either temporarily, until context + * determines which of the other three categories is correct, or for + * lexemes like INVALID, which aren't really lexemes at all, but indicators + * of a parsing error. Note that the codes must be distinct to distinguish + * categories, but need not take the form of a bit array. + */ -#define NUMBER ( LEAF | 1) -#define SCRIPT ( LEAF | 2) -#define BOOLEAN ( LEAF | BAREWORD) -#define BRACED ( LEAF | 4) -#define VARIABLE ( LEAF | 5) -#define QUOTED ( LEAF | 6) -#define EMPTY ( LEAF | 7) +#define BINARY 0x40 /* This lexeme is a binary operator. An + * OpNode representing it should go into the + * parse tree, and two operands should be + * parsed for it in the expression. */ +#define UNARY 0x80 /* This lexeme is a unary operator. An OpNode + * representing it should go into the parse + * tree, and one operand should be parsed for + * it in the expression. */ +#define LEAF 0xC0 /* This lexeme is a leaf operand in the parse + * tree. No OpNode will be placed in the tree + * for it. Either a literal value will be + * appended to the list of literals in this + * expression, or appropriate Tcl_Tokens will + * be appended in a Tcl_Parse struct to + * represent those leaves that require some + * form of substitution. + */ + +/* Uncategorized lexemes */ + +#define PLUS 1 /* Ambiguous. Resolves to UNARY_PLUS or + * BINARY_PLUS according to context. */ +#define MINUS 2 /* Ambiguous. Resolves to UNARY_MINUS or + * BINARY_MINUS according to context. */ +#define BAREWORD 3 /* Ambigous. Resolves to BOOLEAN or to + * FUNCTION or a parse error according to + * context and value. */ +#define INCOMPLETE 4 /* A parse error. Used only when the single + * "=" is encountered. */ +#define INVALID 5 /* A parse error. Used when any punctuation + * appears that's not a supported operator. */ + +/* Leaf lexemes */ + +#define NUMBER ( LEAF | 1) /* For literal numbers */ +#define SCRIPT ( LEAF | 2) /* Command substitution; [foo] */ +#define BOOLEAN ( LEAF | BAREWORD) /* For literal booleans */ +#define BRACED ( LEAF | 4) /* Braced string; {foo bar} */ +#define VARIABLE ( LEAF | 5) /* Variable substitution; $x */ +#define QUOTED ( LEAF | 6) /* Quoted string; "foo $bar [soom]" */ +#define EMPTY ( LEAF | 7) /* Used only for an empty argument + * list to a function. Represents + * the empty string within parens in + * the expression: rand() */ + +/* Unary operator lexemes */ #define UNARY_PLUS ( UNARY | PLUS) #define UNARY_MINUS ( UNARY | MINUS) @@ -49,6 +90,8 @@ #define NOT ( UNARY | 6) #define BIT_NOT ( UNARY | 7) +/* Binary operator lexemes */ + #define BINARY_PLUS ( BINARY | PLUS) #define BINARY_MINUS ( BINARY | MINUS) #define COMMA ( BINARY | 3) |