/*
 * tclCompExpr.c --
 *
 *	This file contains the code to parse and compile Tcl expressions
 *	and implementations of the Tcl commands corresponding to expression
 *	operators, such as the command ::tcl::mathop::+ .
 *
 * Contributions from Don Porter, NIST, 2006-2007. (not subject to US copyright)
 *
 * 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 1.84 2007/08/27 23:30:28 das Exp $
 */

#include "tclInt.h"
#include "tclCompile.h"		/* CompileEnv */

/*
 * Expression parsing takes place in the routine ParseExpr().  It takes a

 *
 * TclCompileExpr --
 *
 *	This procedure compiles a string containing a Tcl expression into Tcl
 *	bytecodes. 
 *
 * Results:
 *	The return value is TCL_OK on a successful compilation and TCL_ERROR
 *	on failure (which must be a syntax error). 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.
 *
 *----------------------------------------------------------------------
 */

    Tcl_Obj *const objv[])
{
    TclOpCmdClientData *occdPtr = (TclOpCmdClientData *)clientData;
    unsigned char lexeme;
    OpNode nodes[2];
    Tcl_Obj *const *litObjv = objv + 1;

    if (objc != 1+occdPtr->numArgs) {
	Tcl_WrongNumArgs(interp, 1, objv, occdPtr->expected);
	return TCL_ERROR;
    }

    ParseLexeme(occdPtr->operator, strlen(occdPtr->operator), &lexeme, NULL);
    nodes[0].lexeme = START;
    nodes[0].mark = MARK_RIGHT;

 *----------------------------------------------------------------------
 *
 * TclVariadicOpCmd --
 *	Implements the commands: +, *, &, |, ^, **
 *	in the ::tcl::mathop namespace.  These commands are defined for
 *	arbitrary number of arguments by repeatedly applying the base
 *	operator with suitable associative rules.  When fewer than two
 *	arguments are provided, suitable basis answers are returned.
 *
 * Results:
 *	A standard Tcl return code and result left in interp.
 *
 * Side effects:
 * 	None.
 *

    Tcl_Obj *const objv[])
{
    TclOpCmdClientData *occdPtr = (TclOpCmdClientData *)clientData;
    unsigned char lexeme;
    int code;

    if (objc < 2) {
	Tcl_SetObjResult(interp, Tcl_NewIntObj(occdPtr->numArgs));
	return TCL_OK;
    }

    ParseLexeme(occdPtr->operator, strlen(occdPtr->operator), &lexeme, NULL);
    lexeme |= BINARY;

    if (objc == 2) {
	Tcl_Obj *litObjv[2];
	OpNode nodes[2];
	int decrMe = 0;
	Tcl_Obj *const *litObjPtrPtr = litObjv;

	if (lexeme == EXPON) {
	    litObjv[1] = Tcl_NewIntObj(occdPtr->numArgs);
	    Tcl_IncrRefCount(litObjv[1]);
	    decrMe = 1;
	    litObjv[0] = objv[1];
	    nodes[0].lexeme = START;
	    nodes[0].mark = MARK_RIGHT;
	    nodes[0].right = 1;
	    nodes[1].lexeme = lexeme;
	    nodes[1].mark = MARK_LEFT;
	    nodes[1].left = OT_LITERAL;
	    nodes[1].right = OT_LITERAL;
	    nodes[1].p.parent = 0;
	} else {
	    if (lexeme == DIVIDE) {
		litObjv[0] = Tcl_NewDoubleObj(1.0);
	    } else {
		litObjv[0] = Tcl_NewIntObj(occdPtr->numArgs);
	    }
	    Tcl_IncrRefCount(litObjv[0]);
	    litObjv[1] = objv[1];
	    nodes[0].lexeme = START;
	    nodes[0].mark = MARK_RIGHT;
	    nodes[0].right = 1;
	    nodes[1].lexeme = lexeme;