/[dtapublic]/projs/trunk/shared_source/c_tcl_base_7_5_w_mods/tclcompexpr.c
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Revision 42 - (hide annotations) (download)
Fri Oct 14 01:50:00 2016 UTC (7 years, 8 months ago) by dashley
Original Path: projs/trunk/shared_source/tcl_base/tclcompexpr.c
File MIME type: text/plain
File size: 33187 byte(s)
Move shared source code to commonize.
1 dashley 25 /* $Header: /cvsroot/esrg/sfesrg/esrgpcpj/shared/tcl_base/tclcompexpr.c,v 1.1.1.1 2001/06/13 04:35:43 dtashley Exp $ */
2    
3     /*
4     * tclCompExpr.c --
5     *
6     * This file contains the code to compile Tcl expressions.
7     *
8     * Copyright (c) 1997 Sun Microsystems, Inc.
9     *
10     * See the file "license.terms" for information on usage and redistribution
11     * of this file, and for a DISCLAIMER OF ALL WARRANTIES.
12     *
13     * RCS: @(#) $Id: tclcompexpr.c,v 1.1.1.1 2001/06/13 04:35:43 dtashley Exp $
14     */
15    
16     #include "tclInt.h"
17     #include "tclCompile.h"
18    
19     /*
20     * The stuff below is a bit of a hack so that this file can be used in
21     * environments that include no UNIX, i.e. no errno: just arrange to use
22     * the errno from tclExecute.c here.
23     */
24    
25     #ifndef TCL_GENERIC_ONLY
26     #include "tclPort.h"
27     #else
28     #define NO_ERRNO_H
29     #endif
30    
31     #ifdef NO_ERRNO_H
32     extern int errno; /* Use errno from tclExecute.c. */
33     #define ERANGE 34
34     #endif
35    
36     /*
37     * Boolean variable that controls whether expression compilation tracing
38     * is enabled.
39     */
40    
41     #ifdef TCL_COMPILE_DEBUG
42     static int traceExprComp = 0;
43     #endif /* TCL_COMPILE_DEBUG */
44    
45     /*
46     * The ExprInfo structure describes the state of compiling an expression.
47     * A pointer to an ExprInfo record is passed among the routines in
48     * this module.
49     */
50    
51     typedef struct ExprInfo {
52     Tcl_Interp *interp; /* Used for error reporting. */
53     Tcl_Parse *parsePtr; /* Structure filled with information about
54     * the parsed expression. */
55     char *expr; /* The expression that was originally passed
56     * to TclCompileExpr. */
57     char *lastChar; /* Points just after last byte of expr. */
58     int hasOperators; /* Set 1 if the expr has operators; 0 if
59     * expr is only a primary. If 1 after
60     * compiling an expr, a tryCvtToNumeric
61     * instruction is emitted to convert the
62     * primary to a number if possible. */
63     int exprIsJustVarRef; /* Set 1 if the expr consists of just a
64     * variable reference as in the expression
65     * of "if $b then...". Otherwise 0. If 1 the
66     * expr is compiled out-of-line in order to
67     * implement expr's 2 level substitution
68     * semantics properly. */
69     int exprIsComparison; /* Set 1 if the top-level operator in the
70     * expr is a comparison. Otherwise 0. If 1,
71     * because the operands might be strings,
72     * the expr is compiled out-of-line in order
73     * to implement expr's 2 level substitution
74     * semantics properly. */
75     } ExprInfo;
76    
77     /*
78     * Definitions of numeric codes representing each expression operator.
79     * The order of these must match the entries in the operatorTable below.
80     * Also the codes for the relational operators (OP_LESS, OP_GREATER,
81     * OP_LE, OP_GE, OP_EQ, and OP_NE) must be consecutive and in that order.
82     * Note that OP_PLUS and OP_MINUS represent both unary and binary operators.
83     */
84    
85     #define OP_MULT 0
86     #define OP_DIVIDE 1
87     #define OP_MOD 2
88     #define OP_PLUS 3
89     #define OP_MINUS 4
90     #define OP_LSHIFT 5
91     #define OP_RSHIFT 6
92     #define OP_LESS 7
93     #define OP_GREATER 8
94     #define OP_LE 9
95     #define OP_GE 10
96     #define OP_EQ 11
97     #define OP_NEQ 12
98     #define OP_BITAND 13
99     #define OP_BITXOR 14
100     #define OP_BITOR 15
101     #define OP_LAND 16
102     #define OP_LOR 17
103     #define OP_QUESTY 18
104     #define OP_LNOT 19
105     #define OP_BITNOT 20
106    
107     /*
108     * Table describing the expression operators. Entries in this table must
109     * correspond to the definitions of numeric codes for operators just above.
110     */
111    
112     static int opTableInitialized = 0; /* 0 means not yet initialized. */
113    
114     TCL_DECLARE_MUTEX(opMutex)
115    
116     typedef struct OperatorDesc {
117     char *name; /* Name of the operator. */
118     int numOperands; /* Number of operands. 0 if the operator
119     * requires special handling. */
120     int instruction; /* Instruction opcode for the operator.
121     * Ignored if numOperands is 0. */
122     } OperatorDesc;
123    
124     OperatorDesc operatorTable[] = {
125     {"*", 2, INST_MULT},
126     {"/", 2, INST_DIV},
127     {"%", 2, INST_MOD},
128     {"+", 0},
129     {"-", 0},
130     {"<<", 2, INST_LSHIFT},
131     {">>", 2, INST_RSHIFT},
132     {"<", 2, INST_LT},
133     {">", 2, INST_GT},
134     {"<=", 2, INST_LE},
135     {">=", 2, INST_GE},
136     {"==", 2, INST_EQ},
137     {"!=", 2, INST_NEQ},
138     {"&", 2, INST_BITAND},
139     {"^", 2, INST_BITXOR},
140     {"|", 2, INST_BITOR},
141     {"&&", 0},
142     {"||", 0},
143     {"?", 0},
144     {"!", 1, INST_LNOT},
145     {"~", 1, INST_BITNOT},
146     {NULL}
147     };
148    
149     /*
150     * Hashtable used to map the names of expression operators to the index
151     * of their OperatorDesc description.
152     */
153    
154     static Tcl_HashTable opHashTable;
155    
156     /*
157     * Declarations for local procedures to this file:
158     */
159    
160     static int CompileCondExpr _ANSI_ARGS_((
161     Tcl_Token *exprTokenPtr, ExprInfo *infoPtr,
162     CompileEnv *envPtr, Tcl_Token **endPtrPtr));
163     static int CompileLandOrLorExpr _ANSI_ARGS_((
164     Tcl_Token *exprTokenPtr, int opIndex,
165     ExprInfo *infoPtr, CompileEnv *envPtr,
166     Tcl_Token **endPtrPtr));
167     static int CompileMathFuncCall _ANSI_ARGS_((
168     Tcl_Token *exprTokenPtr, char *funcName,
169     ExprInfo *infoPtr, CompileEnv *envPtr,
170     Tcl_Token **endPtrPtr));
171     static int CompileSubExpr _ANSI_ARGS_((
172     Tcl_Token *exprTokenPtr, ExprInfo *infoPtr,
173     CompileEnv *envPtr));
174     static void LogSyntaxError _ANSI_ARGS_((ExprInfo *infoPtr));
175    
176     /*
177     * Macro used to debug the execution of the expression compiler.
178     */
179    
180     #ifdef TCL_COMPILE_DEBUG
181     #define TRACE(exprBytes, exprLength, tokenBytes, tokenLength) \
182     if (traceExprComp) { \
183     fprintf(stderr, "CompileSubExpr: \"%.*s\", token \"%.*s\"\n", \
184     (exprLength), (exprBytes), (tokenLength), (tokenBytes)); \
185     }
186     #else
187     #define TRACE(exprBytes, exprLength, tokenBytes, tokenLength)
188     #endif /* TCL_COMPILE_DEBUG */
189    
190     /*
191     *----------------------------------------------------------------------
192     *
193     * TclCompileExpr --
194     *
195     * This procedure compiles a string containing a Tcl expression into
196     * Tcl bytecodes. This procedure is the top-level interface to the
197     * the expression compilation module, and is used by such public
198     * procedures as Tcl_ExprString, Tcl_ExprStringObj, Tcl_ExprLong,
199     * Tcl_ExprDouble, Tcl_ExprBoolean, and Tcl_ExprBooleanObj.
200     *
201     * Results:
202     * The return value is TCL_OK on a successful compilation and TCL_ERROR
203     * on failure. If TCL_ERROR is returned, then the interpreter's result
204     * contains an error message.
205     *
206     * envPtr->maxStackDepth is updated with the maximum number of stack
207     * elements needed to execute the expression.
208     *
209     * envPtr->exprIsJustVarRef is set 1 if the expression consisted of
210     * a single variable reference as in the expression of "if $b then...".
211     * Otherwise it is set 0. This is used to implement Tcl's two level
212     * expression substitution semantics properly.
213     *
214     * envPtr->exprIsComparison is set 1 if the top-level operator in the
215     * expr is a comparison. Otherwise it is set 0. If 1, because the
216     * operands might be strings, the expr is compiled out-of-line in order
217     * to implement expr's 2 level substitution semantics properly.
218     *
219     * Side effects:
220     * Adds instructions to envPtr to evaluate the expression at runtime.
221     *
222     *----------------------------------------------------------------------
223     */
224    
225     int
226     TclCompileExpr(interp, script, numBytes, envPtr)
227     Tcl_Interp *interp; /* Used for error reporting. */
228     char *script; /* The source script to compile. */
229     int numBytes; /* Number of bytes in script. If < 0, the
230     * string consists of all bytes up to the
231     * first null character. */
232     CompileEnv *envPtr; /* Holds resulting instructions. */
233     {
234     ExprInfo info;
235     Tcl_Parse parse;
236     Tcl_HashEntry *hPtr;
237     int maxDepth, new, i, code;
238    
239     /*
240     * If this is the first time we've been called, initialize the table
241     * of expression operators.
242     */
243    
244     if (numBytes < 0) {
245     numBytes = (script? strlen(script) : 0);
246     }
247     if (!opTableInitialized) {
248     Tcl_MutexLock(&opMutex);
249     if (!opTableInitialized) {
250     Tcl_InitHashTable(&opHashTable, TCL_STRING_KEYS);
251     for (i = 0; operatorTable[i].name != NULL; i++) {
252     hPtr = Tcl_CreateHashEntry(&opHashTable,
253     operatorTable[i].name, &new);
254     if (new) {
255     Tcl_SetHashValue(hPtr, (ClientData) i);
256     }
257     }
258     opTableInitialized = 1;
259     }
260     Tcl_MutexUnlock(&opMutex);
261     }
262    
263     /*
264     * Initialize the structure containing information abvout this
265     * expression compilation.
266     */
267    
268     info.interp = interp;
269     info.parsePtr = &parse;
270     info.expr = script;
271     info.lastChar = (script + numBytes);
272     info.hasOperators = 0;
273     info.exprIsJustVarRef = 1; /* will be set 0 if anything else is seen */
274     info.exprIsComparison = 0;
275    
276     /*
277     * Parse the expression then compile it.
278     */
279    
280     maxDepth = 0;
281     code = Tcl_ParseExpr(interp, script, numBytes, &parse);
282     if (code != TCL_OK) {
283     goto done;
284     }
285    
286     code = CompileSubExpr(parse.tokenPtr, &info, envPtr);
287     if (code != TCL_OK) {
288     Tcl_FreeParse(&parse);
289     goto done;
290     }
291     maxDepth = envPtr->maxStackDepth;
292    
293     if (!info.hasOperators) {
294     /*
295     * Attempt to convert the primary's object to an int or double.
296     * This is done in order to support Tcl's policy of interpreting
297     * operands if at all possible as first integers, else
298     * floating-point numbers.
299     */
300    
301     TclEmitOpcode(INST_TRY_CVT_TO_NUMERIC, envPtr);
302     }
303     Tcl_FreeParse(&parse);
304    
305     done:
306     envPtr->maxStackDepth = maxDepth;
307     envPtr->exprIsJustVarRef = info.exprIsJustVarRef;
308     envPtr->exprIsComparison = info.exprIsComparison;
309     return code;
310     }
311    
312     /*
313     *----------------------------------------------------------------------
314     *
315     * TclFinalizeCompilation --
316     *
317     * Clean up the compilation environment so it can later be
318     * properly reinitialized. This procedure is called by
319     * TclFinalizeCompExecEnv() in tclObj.c, which in turn is called
320     * by Tcl_Finalize().
321     *
322     * Results:
323     * None.
324     *
325     * Side effects:
326     * Cleans up the compilation environment. At the moment, just the
327     * table of expression operators is freed.
328     *
329     *----------------------------------------------------------------------
330     */
331    
332     void
333     TclFinalizeCompilation()
334     {
335     Tcl_MutexLock(&opMutex);
336     if (opTableInitialized) {
337     Tcl_DeleteHashTable(&opHashTable);
338     opTableInitialized = 0;
339     }
340     Tcl_MutexUnlock(&opMutex);
341     }
342    
343     /*
344     *----------------------------------------------------------------------
345     *
346     * CompileSubExpr --
347     *
348     * Given a pointer to a TCL_TOKEN_SUB_EXPR token describing a
349     * subexpression, this procedure emits instructions to evaluate the
350     * subexpression at runtime.
351     *
352     * Results:
353     * The return value is TCL_OK on a successful compilation and TCL_ERROR
354     * on failure. If TCL_ERROR is returned, then the interpreter's result
355     * contains an error message.
356     *
357     * envPtr->maxStackDepth is updated with the maximum number of stack
358     * elements needed to execute the subexpression.
359     *
360     * envPtr->exprIsJustVarRef is set 1 if the subexpression consisted of
361     * a single variable reference as in the expression of "if $b then...".
362     * Otherwise it is set 0. This is used to implement Tcl's two level
363     * expression substitution semantics properly.
364     *
365     * envPtr->exprIsComparison is set 1 if the top-level operator in the
366     * subexpression is a comparison. Otherwise it is set 0. If 1, because
367     * the operands might be strings, the expr is compiled out-of-line in
368     * order to implement expr's 2 level substitution semantics properly.
369     *
370     * Side effects:
371     * Adds instructions to envPtr to evaluate the subexpression.
372     *
373     *----------------------------------------------------------------------
374     */
375    
376     static int
377     CompileSubExpr(exprTokenPtr, infoPtr, envPtr)
378     Tcl_Token *exprTokenPtr; /* Points to TCL_TOKEN_SUB_EXPR token
379     * to compile. */
380     ExprInfo *infoPtr; /* Describes the compilation state for the
381     * expression being compiled. */
382     CompileEnv *envPtr; /* Holds resulting instructions. */
383     {
384     Tcl_Interp *interp = infoPtr->interp;
385     Tcl_Token *tokenPtr, *endPtr, *afterSubexprPtr;
386     OperatorDesc *opDescPtr;
387     Tcl_HashEntry *hPtr;
388     char *operator;
389     char savedChar;
390     int maxDepth, objIndex, opIndex, length, code;
391     char buffer[TCL_UTF_MAX];
392    
393     if (exprTokenPtr->type != TCL_TOKEN_SUB_EXPR) {
394     panic("CompileSubExpr: token type %d not TCL_TOKEN_SUB_EXPR\n",
395     exprTokenPtr->type);
396     }
397     maxDepth = 0;
398     code = TCL_OK;
399    
400     /*
401     * Switch on the type of the first token after the subexpression token.
402     * After processing it, advance tokenPtr to point just after the
403     * subexpression's last token.
404     */
405    
406     tokenPtr = exprTokenPtr+1;
407     TRACE(exprTokenPtr->start, exprTokenPtr->size,
408     tokenPtr->start, tokenPtr->size);
409     switch (tokenPtr->type) {
410     case TCL_TOKEN_WORD:
411     code = TclCompileTokens(interp, tokenPtr+1,
412     tokenPtr->numComponents, envPtr);
413     if (code != TCL_OK) {
414     goto done;
415     }
416     maxDepth = envPtr->maxStackDepth;
417     tokenPtr += (tokenPtr->numComponents + 1);
418     infoPtr->exprIsJustVarRef = 0;
419     break;
420    
421     case TCL_TOKEN_TEXT:
422     if (tokenPtr->size > 0) {
423     objIndex = TclRegisterLiteral(envPtr, tokenPtr->start,
424     tokenPtr->size, /*onHeap*/ 0);
425     } else {
426     objIndex = TclRegisterLiteral(envPtr, "", 0, /*onHeap*/ 0);
427     }
428     TclEmitPush(objIndex, envPtr);
429     maxDepth = 1;
430     tokenPtr += 1;
431     infoPtr->exprIsJustVarRef = 0;
432     break;
433    
434     case TCL_TOKEN_BS:
435     length = Tcl_UtfBackslash(tokenPtr->start, (int *) NULL,
436     buffer);
437     if (length > 0) {
438     objIndex = TclRegisterLiteral(envPtr, buffer, length,
439     /*onHeap*/ 0);
440     } else {
441     objIndex = TclRegisterLiteral(envPtr, "", 0, /*onHeap*/ 0);
442     }
443     TclEmitPush(objIndex, envPtr);
444     maxDepth = 1;
445     tokenPtr += 1;
446     infoPtr->exprIsJustVarRef = 0;
447     break;
448    
449     case TCL_TOKEN_COMMAND:
450     code = TclCompileScript(interp, tokenPtr->start+1,
451     tokenPtr->size-2, /*nested*/ 1, envPtr);
452     if (code != TCL_OK) {
453     goto done;
454     }
455     maxDepth = envPtr->maxStackDepth;
456     tokenPtr += 1;
457     infoPtr->exprIsJustVarRef = 0;
458     break;
459    
460     case TCL_TOKEN_VARIABLE:
461     code = TclCompileTokens(interp, tokenPtr, 1, envPtr);
462     if (code != TCL_OK) {
463     goto done;
464     }
465     maxDepth = envPtr->maxStackDepth;
466     tokenPtr += (tokenPtr->numComponents + 1);
467     break;
468    
469     case TCL_TOKEN_SUB_EXPR:
470     infoPtr->exprIsComparison = 0;
471     code = CompileSubExpr(tokenPtr, infoPtr, envPtr);
472     if (code != TCL_OK) {
473     goto done;
474     }
475     maxDepth = envPtr->maxStackDepth;
476     tokenPtr += (tokenPtr->numComponents + 1);
477     break;
478    
479     case TCL_TOKEN_OPERATOR:
480     /*
481     * Look up the operator. Temporarily overwrite the character
482     * just after the end of the operator with a 0 byte. If the
483     * operator isn't found, treat it as a math function.
484     */
485    
486     /*
487     * TODO: Note that the string is modified in place. This is unsafe
488     * and will break if any of the routines called while the string is
489     * modified have side effects that depend on the original string
490     * being unmodified (e.g. adding an entry to the literal table).
491     */
492    
493     operator = tokenPtr->start;
494     savedChar = operator[tokenPtr->size];
495     operator[tokenPtr->size] = 0;
496     hPtr = Tcl_FindHashEntry(&opHashTable, operator);
497     if (hPtr == NULL) {
498     code = CompileMathFuncCall(exprTokenPtr, operator, infoPtr,
499     envPtr, &endPtr);
500     operator[tokenPtr->size] = (char) savedChar;
501     if (code != TCL_OK) {
502     goto done;
503     }
504     maxDepth = envPtr->maxStackDepth;
505     tokenPtr = endPtr;
506     infoPtr->exprIsJustVarRef = 0;
507     infoPtr->exprIsComparison = 0;
508     break;
509     }
510     operator[tokenPtr->size] = (char) savedChar;
511     opIndex = (int) Tcl_GetHashValue(hPtr);
512     opDescPtr = &(operatorTable[opIndex]);
513    
514     /*
515     * If the operator is "normal", compile it using information
516     * from the operator table.
517     */
518    
519     if (opDescPtr->numOperands > 0) {
520     tokenPtr++;
521     code = CompileSubExpr(tokenPtr, infoPtr, envPtr);
522     if (code != TCL_OK) {
523     goto done;
524     }
525     maxDepth = envPtr->maxStackDepth;
526     tokenPtr += (tokenPtr->numComponents + 1);
527    
528     if (opDescPtr->numOperands == 2) {
529     code = CompileSubExpr(tokenPtr, infoPtr, envPtr);
530     if (code != TCL_OK) {
531     goto done;
532     }
533     maxDepth = TclMax((envPtr->maxStackDepth + 1),
534     maxDepth);
535     tokenPtr += (tokenPtr->numComponents + 1);
536     }
537     TclEmitOpcode(opDescPtr->instruction, envPtr);
538     infoPtr->hasOperators = 1;
539     infoPtr->exprIsJustVarRef = 0;
540     infoPtr->exprIsComparison =
541     ((opIndex >= OP_LESS) && (opIndex <= OP_NEQ));
542     break;
543     }
544    
545     /*
546     * The operator requires special treatment, and is either
547     * "+" or "-", or one of "&&", "||" or "?".
548     */
549    
550     switch (opIndex) {
551     case OP_PLUS:
552     case OP_MINUS:
553     tokenPtr++;
554     code = CompileSubExpr(tokenPtr, infoPtr, envPtr);
555     if (code != TCL_OK) {
556     goto done;
557     }
558     maxDepth = envPtr->maxStackDepth;
559     tokenPtr += (tokenPtr->numComponents + 1);
560    
561     /*
562     * Check whether the "+" or "-" is unary.
563     */
564    
565     afterSubexprPtr = exprTokenPtr
566     + exprTokenPtr->numComponents+1;
567     if (tokenPtr == afterSubexprPtr) {
568     TclEmitOpcode(((opIndex==OP_PLUS)?
569     INST_UPLUS : INST_UMINUS),
570     envPtr);
571     break;
572     }
573    
574     /*
575     * The "+" or "-" is binary.
576     */
577    
578     code = CompileSubExpr(tokenPtr, infoPtr, envPtr);
579     if (code != TCL_OK) {
580     goto done;
581     }
582     maxDepth = TclMax((envPtr->maxStackDepth + 1),
583     maxDepth);
584     tokenPtr += (tokenPtr->numComponents + 1);
585     TclEmitOpcode(((opIndex==OP_PLUS)? INST_ADD : INST_SUB),
586     envPtr);
587     break;
588    
589     case OP_LAND:
590     case OP_LOR:
591     code = CompileLandOrLorExpr(exprTokenPtr, opIndex,
592     infoPtr, envPtr, &endPtr);
593     if (code != TCL_OK) {
594     goto done;
595     }
596     maxDepth = envPtr->maxStackDepth;
597     tokenPtr = endPtr;
598     break;
599    
600     case OP_QUESTY:
601     code = CompileCondExpr(exprTokenPtr, infoPtr,
602     envPtr, &endPtr);
603     if (code != TCL_OK) {
604     goto done;
605     }
606     maxDepth = envPtr->maxStackDepth;
607     tokenPtr = endPtr;
608     break;
609    
610     default:
611     panic("CompileSubExpr: unexpected operator %d requiring special treatment\n",
612     opIndex);
613     } /* end switch on operator requiring special treatment */
614     infoPtr->hasOperators = 1;
615     infoPtr->exprIsJustVarRef = 0;
616     infoPtr->exprIsComparison = 0;
617     break;
618    
619     default:
620     panic("CompileSubExpr: unexpected token type %d\n",
621     tokenPtr->type);
622     }
623    
624     /*
625     * Verify that the subexpression token had the required number of
626     * subtokens: that we've advanced tokenPtr just beyond the
627     * subexpression's last token. For example, a "*" subexpression must
628     * contain the tokens for exactly two operands.
629     */
630    
631     if (tokenPtr != (exprTokenPtr + exprTokenPtr->numComponents+1)) {
632     LogSyntaxError(infoPtr);
633     code = TCL_ERROR;
634     }
635    
636     done:
637     envPtr->maxStackDepth = maxDepth;
638     return code;
639     }
640    
641     /*
642     *----------------------------------------------------------------------
643     *
644     * CompileLandOrLorExpr --
645     *
646     * This procedure compiles a Tcl logical and ("&&") or logical or
647     * ("||") subexpression.
648     *
649     * Results:
650     * The return value is TCL_OK on a successful compilation and TCL_ERROR
651     * on failure. If TCL_OK is returned, a pointer to the token just after
652     * the last one in the subexpression is stored at the address in
653     * endPtrPtr. If TCL_ERROR is returned, then the interpreter's result
654     * contains an error message.
655     *
656     * envPtr->maxStackDepth is updated with the maximum number of stack
657     * elements needed to execute the expression.
658     *
659     * Side effects:
660     * Adds instructions to envPtr to evaluate the expression at runtime.
661     *
662     *----------------------------------------------------------------------
663     */
664    
665     static int
666     CompileLandOrLorExpr(exprTokenPtr, opIndex, infoPtr, envPtr, endPtrPtr)
667     Tcl_Token *exprTokenPtr; /* Points to TCL_TOKEN_SUB_EXPR token
668     * containing the "&&" or "||" operator. */
669     int opIndex; /* A code describing the expression
670     * operator: either OP_LAND or OP_LOR. */
671     ExprInfo *infoPtr; /* Describes the compilation state for the
672     * expression being compiled. */
673     CompileEnv *envPtr; /* Holds resulting instructions. */
674     Tcl_Token **endPtrPtr; /* If successful, a pointer to the token
675     * just after the last token in the
676     * subexpression is stored here. */
677     {
678     JumpFixup shortCircuitFixup; /* Used to fix up the short circuit jump
679     * after the first subexpression. */
680     JumpFixup lhsTrueFixup, lhsEndFixup;
681     /* Used to fix up jumps used to convert the
682     * first operand to 0 or 1. */
683     Tcl_Token *tokenPtr;
684     int dist, maxDepth, code;
685    
686     /*
687     * Emit code for the first operand.
688     */
689    
690     maxDepth = 0;
691     tokenPtr = exprTokenPtr+2;
692     code = CompileSubExpr(tokenPtr, infoPtr, envPtr);
693     if (code != TCL_OK) {
694     goto done;
695     }
696     maxDepth = envPtr->maxStackDepth;
697     tokenPtr += (tokenPtr->numComponents + 1);
698    
699     /*
700     * Convert the first operand to the result that Tcl requires:
701     * "0" or "1". Eventually we'll use a new instruction for this.
702     */
703    
704     TclEmitForwardJump(envPtr, TCL_TRUE_JUMP, &lhsTrueFixup);
705     TclEmitPush(TclRegisterLiteral(envPtr, "0", 1, /*onHeap*/ 0), envPtr);
706     TclEmitForwardJump(envPtr, TCL_UNCONDITIONAL_JUMP, &lhsEndFixup);
707     dist = (envPtr->codeNext - envPtr->codeStart) - lhsTrueFixup.codeOffset;
708     if (TclFixupForwardJump(envPtr, &lhsTrueFixup, dist, 127)) {
709     badDist:
710     panic("CompileLandOrLorExpr: bad jump distance %d\n", dist);
711     }
712     TclEmitPush(TclRegisterLiteral(envPtr, "1", 1, /*onHeap*/ 0), envPtr);
713     dist = (envPtr->codeNext - envPtr->codeStart) - lhsEndFixup.codeOffset;
714     if (TclFixupForwardJump(envPtr, &lhsEndFixup, dist, 127)) {
715     goto badDist;
716     }
717    
718     /*
719     * Emit the "short circuit" jump around the rest of the expression.
720     * Duplicate the "0" or "1" on top of the stack first to keep the
721     * jump from consuming it.
722     */
723    
724     TclEmitOpcode(INST_DUP, envPtr);
725     TclEmitForwardJump(envPtr,
726     ((opIndex==OP_LAND)? TCL_FALSE_JUMP : TCL_TRUE_JUMP),
727     &shortCircuitFixup);
728    
729     /*
730     * Emit code for the second operand.
731     */
732    
733     code = CompileSubExpr(tokenPtr, infoPtr, envPtr);
734     if (code != TCL_OK) {
735     goto done;
736     }
737     maxDepth = TclMax((envPtr->maxStackDepth + 1), maxDepth);
738     tokenPtr += (tokenPtr->numComponents + 1);
739    
740     /*
741     * Emit a "logical and" or "logical or" instruction. This does not try
742     * to "short- circuit" the evaluation of both operands, but instead
743     * ensures that we either have a "1" or a "0" result.
744     */
745    
746     TclEmitOpcode(((opIndex==OP_LAND)? INST_LAND : INST_LOR), envPtr);
747    
748     /*
749     * Now that we know the target of the forward jump, update it with the
750     * correct distance.
751     */
752    
753     dist = (envPtr->codeNext - envPtr->codeStart)
754     - shortCircuitFixup.codeOffset;
755     TclFixupForwardJump(envPtr, &shortCircuitFixup, dist, 127);
756     *endPtrPtr = tokenPtr;
757    
758     done:
759     envPtr->maxStackDepth = maxDepth;
760     return code;
761     }
762    
763     /*
764     *----------------------------------------------------------------------
765     *
766     * CompileCondExpr --
767     *
768     * This procedure compiles a Tcl conditional expression:
769     * condExpr ::= lorExpr ['?' condExpr ':' condExpr]
770     *
771     * Results:
772     * The return value is TCL_OK on a successful compilation and TCL_ERROR
773     * on failure. If TCL_OK is returned, a pointer to the token just after
774     * the last one in the subexpression is stored at the address in
775     * endPtrPtr. If TCL_ERROR is returned, then the interpreter's result
776     * contains an error message.
777     *
778     * envPtr->maxStackDepth is updated with the maximum number of stack
779     * elements needed to execute the expression.
780     *
781     * Side effects:
782     * Adds instructions to envPtr to evaluate the expression at runtime.
783     *
784     *----------------------------------------------------------------------
785     */
786    
787     static int
788     CompileCondExpr(exprTokenPtr, infoPtr, envPtr, endPtrPtr)
789     Tcl_Token *exprTokenPtr; /* Points to TCL_TOKEN_SUB_EXPR token
790     * containing the "?" operator. */
791     ExprInfo *infoPtr; /* Describes the compilation state for the
792     * expression being compiled. */
793     CompileEnv *envPtr; /* Holds resulting instructions. */
794     Tcl_Token **endPtrPtr; /* If successful, a pointer to the token
795     * just after the last token in the
796     * subexpression is stored here. */
797     {
798     JumpFixup jumpAroundThenFixup, jumpAroundElseFixup;
799     /* Used to update or replace one-byte jumps
800     * around the then and else expressions when
801     * their target PCs are determined. */
802     Tcl_Token *tokenPtr;
803     int elseCodeOffset, dist, maxDepth, code;
804    
805     /*
806     * Emit code for the test.
807     */
808    
809     maxDepth = 0;
810     tokenPtr = exprTokenPtr+2;
811     code = CompileSubExpr(tokenPtr, infoPtr, envPtr);
812     if (code != TCL_OK) {
813     goto done;
814     }
815     maxDepth = envPtr->maxStackDepth;
816     tokenPtr += (tokenPtr->numComponents + 1);
817    
818     /*
819     * Emit the jump to the "else" expression if the test was false.
820     */
821    
822     TclEmitForwardJump(envPtr, TCL_FALSE_JUMP, &jumpAroundThenFixup);
823    
824     /*
825     * Compile the "then" expression. Note that if a subexpression is only
826     * a primary, we need to try to convert it to numeric. We do this to
827     * support Tcl's policy of interpreting operands if at all possible as
828     * first integers, else floating-point numbers.
829     */
830    
831     infoPtr->hasOperators = 0;
832     code = CompileSubExpr(tokenPtr, infoPtr, envPtr);
833     if (code != TCL_OK) {
834     goto done;
835     }
836     maxDepth = TclMax(envPtr->maxStackDepth, maxDepth);
837     tokenPtr += (tokenPtr->numComponents + 1);
838     if (!infoPtr->hasOperators) {
839     TclEmitOpcode(INST_TRY_CVT_TO_NUMERIC, envPtr);
840     }
841    
842     /*
843     * Emit an unconditional jump around the "else" condExpr.
844     */
845    
846     TclEmitForwardJump(envPtr, TCL_UNCONDITIONAL_JUMP,
847     &jumpAroundElseFixup);
848    
849     /*
850     * Compile the "else" expression.
851     */
852    
853     elseCodeOffset = (envPtr->codeNext - envPtr->codeStart);
854     infoPtr->hasOperators = 0;
855     code = CompileSubExpr(tokenPtr, infoPtr, envPtr);
856     if (code != TCL_OK) {
857     goto done;
858     }
859     maxDepth = TclMax(envPtr->maxStackDepth, maxDepth);
860     tokenPtr += (tokenPtr->numComponents + 1);
861     if (!infoPtr->hasOperators) {
862     TclEmitOpcode(INST_TRY_CVT_TO_NUMERIC, envPtr);
863     }
864    
865     /*
866     * Fix up the second jump around the "else" expression.
867     */
868    
869     dist = (envPtr->codeNext - envPtr->codeStart)
870     - jumpAroundElseFixup.codeOffset;
871     if (TclFixupForwardJump(envPtr, &jumpAroundElseFixup, dist, 127)) {
872     /*
873     * Update the else expression's starting code offset since it
874     * moved down 3 bytes too.
875     */
876    
877     elseCodeOffset += 3;
878     }
879    
880     /*
881     * Fix up the first jump to the "else" expression if the test was false.
882     */
883    
884     dist = (elseCodeOffset - jumpAroundThenFixup.codeOffset);
885     TclFixupForwardJump(envPtr, &jumpAroundThenFixup, dist, 127);
886     *endPtrPtr = tokenPtr;
887    
888     done:
889     envPtr->maxStackDepth = maxDepth;
890     return code;
891     }
892    
893     /*
894     *----------------------------------------------------------------------
895     *
896     * CompileMathFuncCall --
897     *
898     * This procedure compiles a call on a math function in an expression:
899     * mathFuncCall ::= funcName '(' [condExpr {',' condExpr}] ')'
900     *
901     * Results:
902     * The return value is TCL_OK on a successful compilation and TCL_ERROR
903     * on failure. If TCL_OK is returned, a pointer to the token just after
904     * the last one in the subexpression is stored at the address in
905     * endPtrPtr. If TCL_ERROR is returned, then the interpreter's result
906     * contains an error message.
907     *
908     * envPtr->maxStackDepth is updated with the maximum number of stack
909     * elements needed to execute the function.
910     *
911     * Side effects:
912     * Adds instructions to envPtr to evaluate the math function at
913     * runtime.
914     *
915     *----------------------------------------------------------------------
916     */
917    
918     static int
919     CompileMathFuncCall(exprTokenPtr, funcName, infoPtr, envPtr, endPtrPtr)
920     Tcl_Token *exprTokenPtr; /* Points to TCL_TOKEN_SUB_EXPR token
921     * containing the math function call. */
922     char *funcName; /* Name of the math function. */
923     ExprInfo *infoPtr; /* Describes the compilation state for the
924     * expression being compiled. */
925     CompileEnv *envPtr; /* Holds resulting instructions. */
926     Tcl_Token **endPtrPtr; /* If successful, a pointer to the token
927     * just after the last token in the
928     * subexpression is stored here. */
929     {
930     Tcl_Interp *interp = infoPtr->interp;
931     Interp *iPtr = (Interp *) interp;
932     MathFunc *mathFuncPtr;
933     Tcl_HashEntry *hPtr;
934     Tcl_Token *tokenPtr, *afterSubexprPtr;
935     int maxDepth, code, i;
936    
937     /*
938     * Look up the MathFunc record for the function.
939     */
940    
941     code = TCL_OK;
942     maxDepth = 0;
943     hPtr = Tcl_FindHashEntry(&iPtr->mathFuncTable, funcName);
944     if (hPtr == NULL) {
945     Tcl_AppendStringsToObj(Tcl_GetObjResult(interp),
946     "unknown math function \"", funcName, "\"", (char *) NULL);
947     code = TCL_ERROR;
948     goto done;
949     }
950     mathFuncPtr = (MathFunc *) Tcl_GetHashValue(hPtr);
951    
952     /*
953     * If not a builtin function, push an object with the function's name.
954     */
955    
956     if (mathFuncPtr->builtinFuncIndex < 0) {
957     TclEmitPush(TclRegisterLiteral(envPtr, funcName, -1, /*onHeap*/ 0),
958     envPtr);
959     maxDepth = 1;
960     }
961    
962     /*
963     * Compile any arguments for the function.
964     */
965    
966     tokenPtr = exprTokenPtr+2;
967     afterSubexprPtr = exprTokenPtr + (exprTokenPtr->numComponents + 1);
968     if (mathFuncPtr->numArgs > 0) {
969     for (i = 0; i < mathFuncPtr->numArgs; i++) {
970     if (tokenPtr == afterSubexprPtr) {
971     Tcl_ResetResult(interp);
972     Tcl_AppendToObj(Tcl_GetObjResult(interp),
973     "too few arguments for math function", -1);
974     code = TCL_ERROR;
975     goto done;
976     }
977     infoPtr->exprIsComparison = 0;
978     code = CompileSubExpr(tokenPtr, infoPtr, envPtr);
979     if (code != TCL_OK) {
980     goto done;
981     }
982     tokenPtr += (tokenPtr->numComponents + 1);
983     maxDepth++;
984     }
985     if (tokenPtr != afterSubexprPtr) {
986     Tcl_ResetResult(interp);
987     Tcl_AppendToObj(Tcl_GetObjResult(interp),
988     "too many arguments for math function", -1);
989     code = TCL_ERROR;
990     goto done;
991     }
992     } else if (tokenPtr != afterSubexprPtr) {
993     Tcl_ResetResult(interp);
994     Tcl_AppendToObj(Tcl_GetObjResult(interp),
995     "too many arguments for math function", -1);
996     code = TCL_ERROR;
997     goto done;
998     }
999    
1000     /*
1001     * Compile the call on the math function. Note that the "objc" argument
1002     * count for non-builtin functions is incremented by 1 to include the
1003     * function name itself.
1004     */
1005    
1006     if (mathFuncPtr->builtinFuncIndex >= 0) { /* a builtin function */
1007     TclEmitInstInt1(INST_CALL_BUILTIN_FUNC1,
1008     mathFuncPtr->builtinFuncIndex, envPtr);
1009     } else {
1010     TclEmitInstInt1(INST_CALL_FUNC1, (mathFuncPtr->numArgs+1), envPtr);
1011     }
1012     *endPtrPtr = afterSubexprPtr;
1013    
1014     done:
1015     envPtr->maxStackDepth = maxDepth;
1016     return code;
1017     }
1018    
1019     /*
1020     *----------------------------------------------------------------------
1021     *
1022     * LogSyntaxError --
1023     *
1024     * This procedure is invoked after an error occurs when compiling an
1025     * expression. It sets the interpreter result to an error message
1026     * describing the error.
1027     *
1028     * Results:
1029     * None.
1030     *
1031     * Side effects:
1032     * Sets the interpreter result to an error message describing the
1033     * expression that was being compiled when the error occurred.
1034     *
1035     *----------------------------------------------------------------------
1036     */
1037    
1038     static void
1039     LogSyntaxError(infoPtr)
1040     ExprInfo *infoPtr; /* Describes the compilation state for the
1041     * expression being compiled. */
1042     {
1043     int numBytes = (infoPtr->lastChar - infoPtr->expr);
1044     char buffer[100];
1045    
1046     sprintf(buffer, "syntax error in expression \"%.*s\"",
1047     ((numBytes > 60)? 60 : numBytes), infoPtr->expr);
1048     Tcl_AppendStringsToObj(Tcl_GetObjResult(infoPtr->interp),
1049     buffer, (char *) NULL);
1050     }
1051    
1052    
1053     /* $History: tclcompexpr.c $
1054     *
1055     * ***************** Version 1 *****************
1056     * User: Dtashley Date: 1/02/01 Time: 1:27a
1057     * Created in $/IjuScripter, IjuConsole/Source/Tcl Base
1058     * Initial check-in.
1059     */
1060    
1061     /* End of TCLCOMPEXPR.C */

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