cc65/src/ca65/nexttok.c

/*****************************************************************************/
/*                                                                           */
/*			 	   nexttok.c				     */
/*                                                                           */
/*		Get next token and handle token level functions		     */
/*                                                                           */
/*                                                                           */
/*                                                                           */
/* (C) 2000     Ullrich von Bassewitz                                        */
/*              Wacholderweg 14                                              */
/*              D-70597 Stuttgart                                            */
/* EMail:       uz@musoftware.de                                             */
/*                                                                           */
/*                                                                           */
/* This software is provided 'as-is', without any expressed or implied       */
/* warranty.  In no event will the authors be held liable for any damages    */
/* arising from the use of this software.                                    */
/*                                                                           */
/* Permission is granted to anyone to use this software for any purpose,     */
/* including commercial applications, and to alter it and redistribute it    */
/* freely, subject to the following restrictions:                            */
/*                                                                           */
/* 1. The origin of this software must not be misrepresented; you must not   */
/*    claim that you wrote the original software. If you use this software   */
/*    in a product, an acknowledgment in the product documentation would be  */
/*    appreciated but is not required.                                       */
/* 2. Altered source versions must be plainly marked as such, and must not   */
/*    be misrepresented as being the original software.                      */
/* 3. This notice may not be removed or altered from any source              */
/*    distribution.                                                          */
/*                                                                           */
/*****************************************************************************/



#include "error.h"
#include "expr.h"
#include "scanner.h"
#include "toklist.h"
#include "nexttok.h"



/*****************************************************************************/
/*     	       	    		     Code			   	     */
/*****************************************************************************/



static TokList* CollectTokens (unsigned Start, unsigned Count)
/* Read a list of tokens that is terminated by a right paren. For all tokens
 * starting at the one with index Start, and ending at (Start+Count-1), place
 * them into a token list, and return this token list.
 */
{
    /* Create the token list */
    TokList* List = NewTokList ();

    /* Read the token list */
    unsigned Current = 0;
    unsigned Parens  = 0;
    while (Parens != 0 && Tok != TOK_RPAREN) {

    	/* Check for end of line or end of input */
    	if (Tok == TOK_SEP || Tok == TOK_EOF) {
	    Error (ERR_UNEXPECTED_EOL);
	    return List;
	}

	/* Collect tokens in the given range */
	if (Current >= Start && Current < Start+Count) {
	    /* Add the current token to the list */
	    AddCurTok (List);
	}

	/* Check for and count parenthesii */
	if (Tok == TOK_LPAREN) {
	    ++Parens;
	} else if (Tok == TOK_RPAREN) {
	    --Parens;
	}

	/* Get the next token */
	NextTok ();
    }

    /* Eat the closing paren */
    ConsumeRParen ();

    /* Return the list of collected tokens */
    return List;
}



static void FuncMid (void)
/* Handle the .MID function */
{
    long 	Start;
    long       	Count;
    TokList* 	List;

    /* Skip it */
    NextTok ();

    /* Left paren expected */
    ConsumeRParen ();

    /* Start argument */
    Start = ConstExpression ();
    if (Start < 0 || Start > 100) {
	Error (ERR_RANGE);
	Start = 0;
    }
    ConsumeComma ();

    /* Count argument */
    Count = ConstExpression ();
    if (Count > 100) {
	Error (ERR_RANGE);
	Count = 1;
    }
    ConsumeComma ();

    /* Read the token list */
    List = CollectTokens ((unsigned) Start, (unsigned) Count);

    /* Insert it into the scanner feed */



}



void NextTok (void)
/* Get next token and handle token level functions */
{
    /* Get the next raw token */
    NextRawTok ();

    /* Check for token handling functions */
    switch (Tok) {

	case TOK_MID:
	    FuncMid ();
	    break;

	default:
	    /* Quiet down gcc */
	    break;

    }
}



void Consume (enum Token Expected, unsigned ErrMsg)
/* Consume Expected, print an error if we don't find it */
{
    if (Tok == Expected) {
	NextTok ();
    } else {
	Error (ErrMsg);
    }
}



void ConsumeSep (void)
/* Consume a separator token */
{
    /* Accept an EOF as separator */
    if (Tok != TOK_EOF) {
     	if (Tok != TOK_SEP) {
     	    Error (ERR_TOO_MANY_CHARS);
     	    SkipUntilSep ();
     	} else {
     	    NextTok ();
     	}
    }
}



void ConsumeLParen (void)
/* Consume a left paren */
{
    Consume (TOK_LPAREN, ERR_LPAREN_EXPECTED);
}



void ConsumeRParen (void)
/* Consume a right paren */
{
    Consume (TOK_RPAREN, ERR_RPAREN_EXPECTED);
}



void ConsumeComma (void)
/* Consume a comma */
{
    Consume (TOK_COMMA, ERR_COMMA_EXPECTED);
}



void SkipUntilSep (void)
/* Skip tokens until we reach a line separator */
{
    while (Tok != TOK_SEP && Tok != TOK_EOF) {
     	NextTok ();
    }
}