/* * tclCompExpr.c -- * * This file contains the code to compile Tcl expressions. * * Copyright (c) 1997 Sun Microsystems, Inc. * Copyright (c) 1998-2000 by Scriptics Corporation. * * 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 1.30 2005/11/02 14:51:04 dkf Exp $ */ #include "tclInt.h" #include "tclCompile.h" /* * Boolean variable that controls whether expression compilation tracing is * enabled. */ #ifdef TCL_COMPILE_DEBUG static int traceExprComp = 0; #endif /* TCL_COMPILE_DEBUG */ /* * The ExprInfo structure describes the state of compiling an expression. A * pointer to an ExprInfo record is passed among the routines in this module. */ typedef struct ExprInfo { Tcl_Interp *interp; /* Used for error reporting. */ Tcl_Parse *parsePtr; /* Structure filled with information about the * parsed expression. */ CONST char *expr; /* The expression that was originally passed * to TclCompileExpr. */ CONST char *lastChar; /* Points just after last byte of expr. */ int hasOperators; /* Set 1 if the expr has operators; 0 if expr * is only a primary. If 1 after compiling an * expr, a tryCvtToNumeric instruction is * emitted to convert the primary to a number * if possible. */ } ExprInfo; /* * Definitions of numeric codes representing each expression operator. The * order of these must match the entries in the operatorTable below. Also the * codes for the relational operators (OP_LESS, OP_GREATER, OP_LE, OP_GE, * OP_EQ, and OP_NE) must be consecutive and in that order. Note that OP_PLUS * and OP_MINUS represent both unary and binary operators. */ #define OP_MULT 0 #define OP_DIVIDE 1 #define OP_MOD 2 #define OP_PLUS 3 #define OP_MINUS 4 #define OP_LSHIFT 5 #define OP_RSHIFT 6 #define OP_LESS 7 #define OP_GREATER 8 #define OP_LE 9 #define OP_GE 10 #define OP_EQ 11 #define OP_NEQ 12 #define OP_BITAND 13 #define OP_BITXOR 14 #define OP_BITOR 15 #define OP_LAND 16 #define OP_LOR 17 #define OP_QUESTY 18 #define OP_LNOT 19 #define OP_BITNOT 20 #define OP_STREQ 21 #define OP_STRNEQ 22 #define OP_EXPON 23 #define OP_IN_LIST 24 #define OP_NOT_IN_LIST 25 /* * Table describing the expression operators. Entries in this table must * correspond to the definitions of numeric codes for operators just above. */ static int opTableInitialized = 0; /* 0 means not yet initialized. */ TCL_DECLARE_MUTEX(opMutex) typedef struct OperatorDesc { char *name; /* Name of the operator. */ int numOperands; /* Number of operands. 0 if the operator * requires special handling. */ int instruction; /* Instruction opcode for the operator. * Ignored if numOperands is 0. */ } OperatorDesc; static OperatorDesc operatorTable[] = { {"*", 2, INST_MULT}, {"/", 2, INST_DIV}, {"%", 2, INST_MOD}, {"+", 0}, {"-", 0}, {"<<", 2, INST_LSHIFT}, {">>", 2, INST_RSHIFT}, {"<", 2, INST_LT}, {">", 2, INST_GT}, {"<=", 2, INST_LE}, {">=", 2, INST_GE}, {"==", 2, INST_EQ}, {"!=", 2, INST_NEQ}, {"&", 2, INST_BITAND}, {"^", 2, INST_BITXOR}, {"|", 2, INST_BITOR}, {"&&", 0}, {"||", 0}, {"?", 0}, {"!", 1, INST_LNOT}, {"~", 1, INST_BITNOT}, {"eq", 2, INST_STR_EQ}, {"ne", 2, INST_STR_NEQ}, {"**", 2, INST_EXPON}, {"in", 2, INST_LIST_IN}, {"ni", 2, INST_LIST_NOT_IN}, {NULL} }; /* * Hashtable used to map the names of expression operators to the index of * their OperatorDesc description. */ static Tcl_HashTable opHashTable; /* * Declarations for local procedures to this file: */ static int CompileCondExpr( Tcl_Token *exprTokenPtr, ExprInfo *infoPtr, CompileEnv *envPtr, Tcl_Token **endPtrPtr); static int CompileLandOrLorExpr( Tcl_Token *exprTokenPtr, int opIndex, ExprInfo *infoPtr, CompileEnv *envPtr, Tcl_Token **endPtrPtr); static int CompileMathFuncCall(Tcl_Token *exprTokenPtr, CONST char *funcName, ExprInfo *infoPtr, CompileEnv *envPtr, Tcl_Token **endPtrPtr); static int CompileSubExpr(Tcl_Token *exprTokenPtr, ExprInfo *infoPtr, CompileEnv *envPtr); static void LogSyntaxError(ExprInfo *infoPtr); /* * Macro used to debug the execution of the expression compiler. */ #ifdef TCL_COMPILE_DEBUG #define TRACE(exprBytes, exprLength, tokenBytes, tokenLength) \ if (traceExprComp) { \ fprintf(stderr, "CompileSubExpr: \"%.*s\", token \"%.*s\"\n", \ (exprLength), (exprBytes), (tokenLength), (tokenBytes)); \ } #else #define TRACE(exprBytes, exprLength, tokenBytes, tokenLength) #endif /* TCL_COMPILE_DEBUG */ /* *---------------------------------------------------------------------- * * TclCompileExpr -- * * This procedure compiles a string containing a Tcl expression into Tcl * bytecodes. This procedure is the top-level interface to the the * expression compilation module, and is used by such public procedures * as Tcl_ExprString, Tcl_ExprStringObj, Tcl_ExprLong, Tcl_ExprDouble, * Tcl_ExprBoolean, and Tcl_ExprBooleanObj. * * Results: * The return value is TCL_OK on a successful compilation and TCL_ERROR * on failure. If TCL_ERROR is returned, then the interpreter's result * contains an error message. * * Side effects: * Adds instructions to envPtr to evaluate the expression at runtime. * *---------------------------------------------------------------------- */ int TclCompileExpr( Tcl_Interp *interp, /* Used for error reporting. */ CONST char *script, /* The source script to compile. */ int numBytes, /* Number of bytes in script. If < 0, the * string consists of all bytes up to the * first null character. */ CompileEnv *envPtr) /* Holds resulting instructions. */ { ExprInfo info; Tcl_Parse parse; Tcl_HashEntry *hPtr; int new, i, code; /* * If this is the first time we've been called, initialize the table of * expression operators. */ if (numBytes < 0) { numBytes = (script? strlen(script) : 0); } if (!opTableInitialized) { Tcl_MutexLock(&opMutex); if (!opTableInitialized) { Tcl_InitHashTable(&opHashTable, TCL_STRING_KEYS); for (i = 0; operatorTable[i].name != NULL; i++) { hPtr = Tcl_CreateHashEntry(&opHashTable, operatorTable[i].name, &new); if (new) { Tcl_SetHashValue(hPtr, (ClientData) i); } } opTableInitialized = 1; } Tcl_MutexUnlock(&opMutex); } /* * Initialize the structure containing information abvout this expression * compilation. */ info.interp = interp; info.parsePtr = &parse; info.expr = script; info.lastChar = (script + numBytes); info.hasOperators = 0; /* * Parse the expression then compile it. */ code = Tcl_ParseExpr(interp, script, numBytes, &parse); if (code != TCL_OK) { goto done; } code = CompileSubExpr(parse.tokenPtr, &info, envPtr); if (code != TCL_OK) { Tcl_FreeParse(&parse); goto done; } if (!info.hasOperators) { /* * Attempt to convert the primary's object to an int or double. This * is done in order to support Tcl's policy of interpreting operands * if at all possible as first integers, else floating-point numbers. */ TclEmitOpcode(INST_TRY_CVT_TO_NUMERIC, envPtr); } Tcl_FreeParse(&parse); done: return code; } /* *---------------------------------------------------------------------- * * TclFinalizeCompilation -- * * Clean up the compilation environment so it can later be properly * reinitialized. This procedure is called by Tcl_Finalize(). * * Results: * None. * * Side effects: * Cleans up the compilation environment. At the moment, just the table * of expression operators is freed. * *---------------------------------------------------------------------- */ void TclFinalizeCompilation(void) { Tcl_MutexLock(&opMutex); if (opTableInitialized) { Tcl_DeleteHashTable(&opHashTable); opTableInitialized = 0; } Tcl_MutexUnlock(&opMutex); } /* *---------------------------------------------------------------------- * * CompileSubExpr -- * * Given a pointer to a TCL_TOKEN_SUB_EXPR token describing a * subexpression, this procedure emits instructions to evaluate the * subexpression at runtime. * * Results: * The return value is TCL_OK on a successful compilation and TCL_ERROR * on failure. If TCL_ERROR is returned, then the interpreter's result * contains an error message. * * Side effects: * Adds instructions to envPtr to evaluate the subexpression. * *---------------------------------------------------------------------- */ static int CompileSubExpr( Tcl_Token *exprTokenPtr, /* Points to TCL_TOKEN_SUB_EXPR token to * compile. */ ExprInfo *infoPtr, /* Describes the compilation state for the * expression being compiled. */ CompileEnv *envPtr) /* Holds resulting instructions. */ { Tcl_Interp *interp = infoPtr->interp; Tcl_Token *tokenPtr, *endPtr, *afterSubexprPtr; OperatorDesc *opDescPtr; Tcl_HashEntry *hPtr; CONST char *operator; Tcl_DString opBuf; int objIndex, opIndex, length, code; char buffer[TCL_UTF_MAX]; if (exprTokenPtr->type != TCL_TOKEN_SUB_EXPR) { Tcl_Panic("CompileSubExpr: token type %d not TCL_TOKEN_SUB_EXPR\n", exprTokenPtr->type); } code = TCL_OK; /* * Switch on the type of the first token after the subexpression token. * After processing it, advance tokenPtr to point just after the * subexpression's last token. */ tokenPtr = exprTokenPtr+1; TRACE(exprTokenPtr->start, exprTokenPtr->size, tokenPtr->start, tokenPtr->size); switch (tokenPtr->type) { case TCL_TOKEN_WORD: TclCompileTokens(interp, tokenPtr+1, tokenPtr->numComponents, envPtr); tokenPtr += (tokenPtr->numComponents + 1); break; case TCL_TOKEN_TEXT: if (tokenPtr->size > 0) { objIndex = TclRegisterNewLiteral(envPtr, tokenPtr->start, tokenPtr->size); } else { objIndex = TclRegisterNewLiteral(envPtr, "", 0); } TclEmitPush(objIndex, envPtr); tokenPtr += 1; break; case TCL_TOKEN_BS: length = Tcl_UtfBackslash(tokenPtr->start, NULL, buffer); if (length > 0) { objIndex = TclRegisterNewLiteral(envPtr, buffer, length); } else { objIndex = TclRegisterNewLiteral(envPtr, "", 0); } TclEmitPush(objIndex, envPtr); tokenPtr += 1; break; case TCL_TOKEN_COMMAND: TclCompileScript(interp, tokenPtr->start+1, tokenPtr->size-2, envPtr); tokenPtr += 1; break; case TCL_TOKEN_VARIABLE: TclCompileTokens(interp, tokenPtr, 1, envPtr); tokenPtr += (tokenPtr->numComponents + 1); break; case TCL_TOKEN_SUB_EXPR: code = CompileSubExpr(tokenPtr, infoPtr, envPtr); if (code != TCL_OK) { goto done; } tokenPtr += (tokenPtr->numComponents + 1); break; case TCL_TOKEN_OPERATOR: /* * Look up the operator. If the operator isn't found, treat it as a * math function. */ Tcl_DStringInit(&opBuf); operator = Tcl_DStringAppend(&opBuf, tokenPtr->start, tokenPtr->size); hPtr = Tcl_FindHashEntry(&opHashTable, operator); if (hPtr == NULL) { code = CompileMathFuncCall(exprTokenPtr, operator, infoPtr, envPtr, &endPtr); Tcl_DStringFree(&opBuf); if (code != TCL_OK) { goto done; } tokenPtr = endPtr; break; } Tcl_DStringFree(&opBuf); opIndex = (int) Tcl_GetHashValue(hPtr); opDescPtr = &(operatorTable[opIndex]); /* * If the operator is "normal", compile it using information from the * operator table. */ if (opDescPtr->numOperands > 0) { tokenPtr++; code = CompileSubExpr(tokenPtr, infoPtr, envPtr); if (code != TCL_OK) { goto done; } tokenPtr += (tokenPtr->numComponents + 1); if (opDescPtr->numOperands == 2) { code = CompileSubExpr(tokenPtr, infoPtr, envPtr); if (code != TCL_OK) { goto done; } tokenPtr += (tokenPtr->numComponents + 1); } TclEmitOpcode(opDescPtr->instruction, envPtr); infoPtr->hasOperators = 1; break; } /* * The operator requires special treatment, and is either "+" or "-", * or one of "&&", "||" or "?". */ switch (opIndex) { case OP_PLUS: case OP_MINUS: tokenPtr++; code = CompileSubExpr(tokenPtr, infoPtr, envPtr); if (code != TCL_OK) { goto done; } tokenPtr += (tokenPtr->numComponents + 1); /* * Check whether the "+" or "-" is unary. */ afterSubexprPtr = exprTokenPtr + exprTokenPtr->numComponents+1; if (tokenPtr == afterSubexprPtr) { TclEmitOpcode(((opIndex==OP_PLUS)? INST_UPLUS : INST_UMINUS), envPtr); break; } /* * The "+" or "-" is binary. */ code = CompileSubExpr(tokenPtr, infoPtr, envPtr); if (code != TCL_OK) { goto done; } tokenPtr += (tokenPtr->numComponents + 1); TclEmitOpcode(((opIndex==OP_PLUS)? INST_ADD : INST_SUB), envPtr); break; case OP_LAND: case OP_LOR: code = CompileLandOrLorExpr(exprTokenPtr, opIndex, infoPtr, envPtr, &endPtr); if (code != TCL_OK) { goto done; } tokenPtr = endPtr; break; case OP_QUESTY: code = CompileCondExpr(exprTokenPtr, infoPtr, envPtr, &endPtr); if (code != TCL_OK) { goto done; } tokenPtr = endPtr; break; default: Tcl_Panic("CompileSubExpr: unexpected operator %d requiring special treatment\n", opIndex); } /* end switch on operator requiring special treatment */ infoPtr->hasOperators = 1; break; default: Tcl_Panic("CompileSubExpr: unexpected token type %d\n", tokenPtr->type); } /* * Verify that the subexpression token had the required number of * subtokens: that we've advanced tokenPtr just beyond the subexpression's * last token. For example, a "*" subexpression must contain the tokens * for exactly two operands. */ if (tokenPtr != (exprTokenPtr + exprTokenPtr->numComponents+1)) { LogSyntaxError(infoPtr); code = TCL_ERROR; } done: return code; } /* *---------------------------------------------------------------------- * * CompileLandOrLorExpr -- * * This procedure compiles a Tcl logical and ("&&") or logical or ("||") * subexpression. * * Results: * The return value is TCL_OK on a successful compilation and TCL_ERROR * on failure. If TCL_OK is returned, a pointer to the token just after * the last one in the subexpression is stored at the address in * endPtrPtr. If TCL_ERROR is returned, then the interpreter's result * contains an error message. * * Side effects: * Adds instructions to envPtr to evaluate the expression at runtime. * *---------------------------------------------------------------------- */ static int CompileLandOrLorExpr( Tcl_Token *exprTokenPtr, /* Points to TCL_TOKEN_SUB_EXPR token * containing the "&&" or "||" operator. */ int opIndex, /* A code describing the expression operator: * either OP_LAND or OP_LOR. */ ExprInfo *infoPtr, /* Describes the compilation state for the * expression being compiled. */ CompileEnv *envPtr, /* Holds resulting instructions. */ Tcl_Token **endPtrPtr) /* If successful, a pointer to the token just * after the last token in the subexpression * is stored here. */ { JumpFixup shortCircuitFixup;/* Used to fix up the short circuit jump after * the first subexpression. */ JumpFixup shortCircuitFixup2; /* Used to fix up the second jump to the * short-circuit target. */ JumpFixup endFixup; /* Used to fix up jump to the end. */ Tcl_Token *tokenPtr; int code; int savedStackDepth = envPtr->currStackDepth; /* * Emit code for the first operand. */ tokenPtr = exprTokenPtr+2; code = CompileSubExpr(tokenPtr, infoPtr, envPtr); if (code != TCL_OK) { goto done; } tokenPtr += (tokenPtr->numComponents + 1); /* * Emit the short-circuit jump. */ TclEmitForwardJump(envPtr, ((opIndex==OP_LAND)? TCL_FALSE_JUMP : TCL_TRUE_JUMP), &shortCircuitFixup); /* * Emit code for the second operand. */ code = CompileSubExpr(tokenPtr, infoPtr, envPtr); if (code != TCL_OK) { goto done; } tokenPtr += (tokenPtr->numComponents + 1); /* * The result is the boolean value of the second operand. We code this in * a somewhat contorted manner to be able to reuse the shortCircuit value * and save one INST_JUMP. */ TclEmitForwardJump(envPtr, ((opIndex==OP_LAND)? TCL_FALSE_JUMP : TCL_TRUE_JUMP), &shortCircuitFixup2); if (opIndex == OP_LAND) { TclEmitPush(TclRegisterNewLiteral(envPtr, "1", 1), envPtr); } else { TclEmitPush(TclRegisterNewLiteral(envPtr, "0", 1), envPtr); } TclEmitForwardJump(envPtr, TCL_UNCONDITIONAL_JUMP, &endFixup); /* * Fixup the short-circuit jumps and push the shortCircuit value. Note * that shortCircuitFixup2 is always a short jump. */ TclFixupForwardJumpToHere(envPtr, &shortCircuitFixup2, 127); if (TclFixupForwardJumpToHere(envPtr, &shortCircuitFixup, 127)) { /* * shortCircuit jump grown by 3 bytes: update endFixup. */ endFixup.codeOffset += 3; } if (opIndex == OP_LAND) { TclEmitPush(TclRegisterNewLiteral(envPtr, "0", 1), envPtr); } else { TclEmitPush(TclRegisterNewLiteral(envPtr, "1", 1), envPtr); } TclFixupForwardJumpToHere(envPtr, &endFixup, 127); *endPtrPtr = tokenPtr; done: envPtr->currStackDepth = savedStackDepth + 1; return code; } /* *---------------------------------------------------------------------- * * CompileCondExpr -- * * This procedure compiles a Tcl conditional expression: * condExpr ::= lorExpr ['?' condExpr ':' condExpr] * * Results: * The return value is TCL_OK on a successful compilation and TCL_ERROR * on failure. If TCL_OK is returned, a pointer to the token just after * the last one in the subexpression is stored at the address in * endPtrPtr. If TCL_ERROR is returned, then the interpreter's result * contains an error message. * * Side effects: * Adds instructions to envPtr to evaluate the expression at runtime. * *---------------------------------------------------------------------- */ static int CompileCondExpr( Tcl_Token *exprTokenPtr, /* Points to TCL_TOKEN_SUB_EXPR token * containing the "?" operator. */ ExprInfo *infoPtr, /* Describes the compilation state for the * expression being compiled. */ CompileEnv *envPtr, /* Holds resulting instructions. */ Tcl_Token **endPtrPtr) /* If successful, a pointer to the token just * after the last token in the subexpression * is stored here. */ { JumpFixup jumpAroundThenFixup, jumpAroundElseFixup; /* Used to update or replace one-byte jumps * around the then and else expressions when * their target PCs are determined. */ Tcl_Token *tokenPtr; int elseCodeOffset, dist, code; int savedStackDepth = envPtr->currStackDepth; /* * Emit code for the test. */ tokenPtr = exprTokenPtr+2; code = CompileSubExpr(tokenPtr, infoPtr, envPtr); if (code != TCL_OK) { goto done; } tokenPtr += (tokenPtr->numComponents + 1); /* * Emit the jump to the "else" expression if the test was false. */ TclEmitForwardJump(envPtr, TCL_FALSE_JUMP, &jumpAroundThenFixup); /* * Compile the "then" expression. Note that if a subexpression is only a * primary, we need to try to convert it to numeric. We do this to support * Tcl's policy of interpreting operands if at all possible as first * integers, else floating-point numbers. */ infoPtr->hasOperators = 0; code = CompileSubExpr(tokenPtr, infoPtr, envPtr); if (code != TCL_OK) { goto done; } tokenPtr += (tokenPtr->numComponents + 1); if (!infoPtr->hasOperators) { TclEmitOpcode(INST_TRY_CVT_TO_NUMERIC, envPtr); } /* * Emit an unconditional jump around the "else" condExpr. */ TclEmitForwardJump(envPtr, TCL_UNCONDITIONAL_JUMP, &jumpAroundElseFixup); /* * Compile the "else" expression. */ envPtr->currStackDepth = savedStackDepth; elseCodeOffset = (envPtr->codeNext - envPtr->codeStart); infoPtr->hasOperators = 0; code = CompileSubExpr(tokenPtr, infoPtr, envPtr); if (code != TCL_OK) { goto done; } tokenPtr += (tokenPtr->numComponents + 1); if (!infoPtr->hasOperators) { TclEmitOpcode(INST_TRY_CVT_TO_NUMERIC, envPtr); } /* * Fix up the second jump around the "else" expression. */ dist = (envPtr->codeNext - envPtr->codeStart) - jumpAroundElseFixup.codeOffset; if (TclFixupForwardJump(envPtr, &jumpAroundElseFixup, dist, 127)) { /* * Update the else expression's starting code offset since it moved * down 3 bytes too. */ elseCodeOffset += 3; } /* * Fix up the first jump to the "else" expression if the test was false. */ dist = (elseCodeOffset - jumpAroundThenFixup.codeOffset); TclFixupForwardJump(envPtr, &jumpAroundThenFixup, dist, 127); *endPtrPtr = tokenPtr; done: envPtr->currStackDepth = savedStackDepth + 1; return code; } /* *---------------------------------------------------------------------- * * CompileMathFuncCall -- * * This procedure compiles a call on a math function in an expression: * mathFuncCall ::= funcName '(' [condExpr {',' condExpr}] ')' * * Results: * The return value is TCL_OK on a successful compilation and TCL_ERROR * on failure. If TCL_OK is returned, a pointer to the token just after * the last one in the subexpression is stored at the address in * endPtrPtr. If TCL_ERROR is returned, then the interpreter's result * contains an error message. * * Side effects: * Adds instructions to envPtr to evaluate the math function at * runtime. * *---------------------------------------------------------------------- */ static int CompileMathFuncCall( Tcl_Token *exprTokenPtr, /* Points to TCL_TOKEN_SUB_EXPR token * containing the math function call. */ CONST char *funcName, /* Name of the math function. */ ExprInfo *infoPtr, /* Describes the compilation state for the * expression being compiled. */ CompileEnv *envPtr, /* Holds resulting instructions. */ Tcl_Token **endPtrPtr) /* If successful, a pointer to the token just * after the last token in the subexpression * is stored here. */ { Tcl_DString cmdName; int objIndex; Tcl_Token *tokenPtr, *afterSubexprPtr; int argCount; int code = TCL_OK; /* * Prepend "tcl::mathfunc::" to the function name, to produce the name of * a command that evaluates the function. Push that command name on the * stack, in a literal registered to the namespace so that resolution can * be cached. */ Tcl_DStringInit(&cmdName); Tcl_DStringAppend(&cmdName, "tcl::mathfunc::", -1); Tcl_DStringAppend(&cmdName, funcName, -1); objIndex = TclRegisterNewNSLiteral(envPtr, Tcl_DStringValue(&cmdName), Tcl_DStringLength(&cmdName)); TclEmitPush(objIndex, envPtr); Tcl_DStringFree(&cmdName); /* * Compile any arguments for the function. */ argCount = 1; tokenPtr = exprTokenPtr+2; afterSubexprPtr = exprTokenPtr + (exprTokenPtr->numComponents + 1); while (tokenPtr != afterSubexprPtr) { ++argCount; code = CompileSubExpr(tokenPtr, infoPtr, envPtr); if (code != TCL_OK) { return code; } tokenPtr += (tokenPtr->numComponents + 1); } /* Invoke the function */ if (argCount < 255) { TclEmitInstInt1(INST_INVOKE_STK1, argCount, envPtr); } else { TclEmitInstInt4(INST_INVOKE_STK4, argCount, envPtr); } *endPtrPtr = afterSubexprPtr; return TCL_OK; } /* *---------------------------------------------------------------------- * * LogSyntaxError -- * * This procedure is invoked after an error occurs when compiling an * expression. It sets the interpreter result to an error message * describing the error. * * Results: * None. * * Side effects: * Sets the interpreter result to an error message describing the * expression that was being compiled when the error occurred. * *---------------------------------------------------------------------- */ static void LogSyntaxError( ExprInfo *infoPtr) /* Describes the compilation state for the * expression being compiled. */ { Tcl_Obj *result = Tcl_NewStringObj("syntax error in expression \"", -1); TclAppendLimitedToObj(result, infoPtr->expr, (int)(infoPtr->lastChar - infoPtr->expr), 60, ""); Tcl_AppendToObj(result, "\"", -1); Tcl_SetObjResult(infoPtr->interp, result); } /* * Local Variables: * mode: c * c-basic-offset: 4 * fill-column: 78 * End: */