/* 
 * 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 1.11 2002/07/19 12:31:09 dkf Exp $
 */

#include "tclInt.h"
#include "tclCompile.h"

/*
 * The stuff below is a bit of a hack so that this file can be used in

 * this module.
 */

typedef struct ExprInfo {
    Tcl_Interp *interp;		/* Used for error reporting. */
    Tcl_Parse *parsePtr;	/* Structure filled with information about
				 * the parsed expression. */
    char *expr;			/* The expression that was originally passed
				 * to TclCompileExpr. */
    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;

			    Tcl_Token *exprTokenPtr, ExprInfo *infoPtr,
			    CompileEnv *envPtr, Tcl_Token **endPtrPtr));
static int		CompileLandOrLorExpr _ANSI_ARGS_((
			    Tcl_Token *exprTokenPtr, int opIndex,
			    ExprInfo *infoPtr, CompileEnv *envPtr,
			    Tcl_Token **endPtrPtr));
static int		CompileMathFuncCall _ANSI_ARGS_((
			    Tcl_Token *exprTokenPtr, char *funcName,
			    ExprInfo *infoPtr, CompileEnv *envPtr,
			    Tcl_Token **endPtrPtr));
static int		CompileSubExpr _ANSI_ARGS_((
			    Tcl_Token *exprTokenPtr, ExprInfo *infoPtr,
			    CompileEnv *envPtr));
static void		LogSyntaxError _ANSI_ARGS_((ExprInfo *infoPtr));

 *
 *----------------------------------------------------------------------
 */

int
TclCompileExpr(interp, script, numBytes, envPtr)
    Tcl_Interp *interp;		/* Used for error reporting. */
    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;

				 * expression being compiled. */
    CompileEnv *envPtr;		/* Holds resulting instructions. */
{
    Tcl_Interp *interp = infoPtr->interp;
    Tcl_Token *tokenPtr, *endPtr, *afterSubexprPtr;
    OperatorDesc *opDescPtr;
    Tcl_HashEntry *hPtr;
    char *operator;
    char savedChar;
    int objIndex, opIndex, length, code;
    char buffer[TCL_UTF_MAX];

    if (exprTokenPtr->type != TCL_TOKEN_SUB_EXPR) {
	panic("CompileSubExpr: token type %d not TCL_TOKEN_SUB_EXPR\n",
	        exprTokenPtr->type);
    }

		goto done;
	    }
	    tokenPtr += (tokenPtr->numComponents + 1);
	    break;
	    
        case TCL_TOKEN_TEXT:
	    if (tokenPtr->size > 0) {
		objIndex = TclRegisterLiteral(envPtr, tokenPtr->start,
	                tokenPtr->size, /*onHeap*/ 0);
	    } else {
		objIndex = TclRegisterLiteral(envPtr, "", 0, /*onHeap*/ 0);
	    }
	    TclEmitPush(objIndex, envPtr);
	    tokenPtr += 1;
	    break;
	    
        case TCL_TOKEN_BS:
	    length = Tcl_UtfBackslash(tokenPtr->start, (int *) NULL,
		    buffer);
	    if (length > 0) {
		objIndex = TclRegisterLiteral(envPtr, buffer, length,
	                /*onHeap*/ 0);
	    } else {
		objIndex = TclRegisterLiteral(envPtr, "", 0, /*onHeap*/ 0);
	    }
	    TclEmitPush(objIndex, envPtr);
	    tokenPtr += 1;
	    break;
	    
        case TCL_TOKEN_COMMAND:
	    code = TclCompileScript(interp, tokenPtr->start+1,

		goto done;
	    }
	    tokenPtr += (tokenPtr->numComponents + 1);
	    break;
	    
        case TCL_TOKEN_OPERATOR:
	    /*
	     * Look up the operator. Temporarily overwrite the character
	     * just after the end of the operator with a 0 byte. If the
	     * operator isn't found, treat it as a math function.
	     */

	    /*
	     * TODO: Note that the string is modified in place.  This is unsafe
	     * and will break if any of the routines called while the string is
	     * modified have side effects that depend on the original string
	     * being unmodified (e.g. adding an entry to the literal table).
	     */

	    operator = tokenPtr->start;
	    savedChar = operator[tokenPtr->size];
	    operator[tokenPtr->size] = 0;
	    hPtr = Tcl_FindHashEntry(&opHashTable, operator);
	    if (hPtr == NULL) {
		code = CompileMathFuncCall(exprTokenPtr, operator, infoPtr,
			envPtr, &endPtr);
		operator[tokenPtr->size] = (char) savedChar;
		if (code != TCL_OK) {
		    goto done;
		}
		tokenPtr = endPtr;
		break;
	    }
	    operator[tokenPtr->size] = (char) savedChar;
	    opIndex = (int) Tcl_GetHashValue(hPtr);
	    opDescPtr = &(operatorTable[opIndex]);

	    /*
	     * If the operator is "normal", compile it using information
	     * from the operator table.
	     */

    /*
     * Convert the first operand to the result that Tcl requires:
     * "0" or "1". Eventually we'll use a new instruction for this.
     */
    
    TclEmitForwardJump(envPtr, TCL_TRUE_JUMP, &lhsTrueFixup);
    TclEmitPush(TclRegisterLiteral(envPtr, "0", 1, /*onHeap*/ 0), envPtr);
    TclEmitForwardJump(envPtr, TCL_UNCONDITIONAL_JUMP, &lhsEndFixup);
    dist = (envPtr->codeNext - envPtr->codeStart) - lhsTrueFixup.codeOffset;
    if (TclFixupForwardJump(envPtr, &lhsTrueFixup, dist, 127)) {
        badDist:
	panic("CompileLandOrLorExpr: bad jump distance %d\n", dist);
    }
    envPtr->currStackDepth = savedStackDepth;
    TclEmitPush(TclRegisterLiteral(envPtr, "1", 1, /*onHeap*/ 0), envPtr);
    dist = (envPtr->codeNext - envPtr->codeStart) - lhsEndFixup.codeOffset;
    if (TclFixupForwardJump(envPtr, &lhsEndFixup, dist, 127)) {
	goto badDist;
    }

    /*
     * Emit the "short circuit" jump around the rest of the expression.

 *----------------------------------------------------------------------
 */

static int
CompileMathFuncCall(exprTokenPtr, funcName, infoPtr, envPtr, endPtrPtr)
    Tcl_Token *exprTokenPtr;	/* Points to TCL_TOKEN_SUB_EXPR token
				 * containing the math function call. */
    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. */
{

    mathFuncPtr = (MathFunc *) Tcl_GetHashValue(hPtr);

    /*
     * If not a builtin function, push an object with the function's name.
     */

    if (mathFuncPtr->builtinFuncIndex < 0) {
	TclEmitPush(TclRegisterLiteral(envPtr, funcName, -1, /*onHeap*/ 0),
	        envPtr);
    }

    /*
     * Compile any arguments for the function.
     */

    tokenPtr = exprTokenPtr+2;