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bwbasic-2.10.sit
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bwb_cnd.c
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1993-11-09
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/***************************************************************
bwb_cnd.c Conditional Expressions and Commands
for Bywater BASIC Interpreter
Copyright (c) 1993, Ted A. Campbell
Bywater Software
email: tcamp@delphi.com
Copyright and Permissions Information:
All U.S. and international rights are claimed by the author,
Ted A. Campbell.
This software is released under the terms of the GNU General
Public License (GPL), which is distributed with this software
in the file "COPYING". The GPL specifies the terms under
which users may copy and use the software in this distribution.
A separate license is available for commercial distribution,
for information on which you should contact the author.
***************************************************************/
#include <stdio.h>
#include <math.h>
#include <ctype.h>
#include "bwbasic.h"
#include "bwb_mes.h"
/* declarations of functions visible to this file only */
#if ANSI_C
static int cnd_thenels( char *buffer, int position, int *then, int *els );
static int cnd_tostep( char *buffer, int position, int *to, int *step );
static struct bwb_line *find_wend( struct bwb_line *l );
static struct bwb_line *find_endif( struct bwb_line *l,
struct bwb_line **else_line );
static int is_endif( struct bwb_line *l );
extern int var_setnval( struct bwb_variable *v, bnumber i );
static int case_eval( struct exp_ese *expression, struct exp_ese *minval,
struct exp_ese *maxval );
static struct bwb_line *find_case( struct bwb_line *l );
static struct bwb_line *find_endselect( struct bwb_line *l );
static int is_endselect( struct bwb_line *l );
static struct bwb_line *bwb_caseif( struct bwb_line *l );
#if STRUCT_CMDS
static struct bwb_line *find_next( struct bwb_line *l );
#endif
#else
static int cnd_thenels();
static int cnd_tostep();
static struct bwb_line *find_wend();
static struct bwb_line *find_endif();
static int is_endif();
extern int var_setnval();
static int case_eval();
static struct bwb_line *find_case();
static struct bwb_line *find_endselect();
static int is_endselect();
static struct bwb_line *bwb_caseif();
#if STRUCT_CMDS
static struct bwb_line *find_next();
#endif
#endif /* ANSI_C for prototypes */
/*** IF-THEN-ELSE ***/
/***************************************************************
FUNCTION: bwb_if()
DESCRIPTION: This function handles the BASIC IF
statement.
SYNTAX: IF expression THEN [statement [ELSE statement]]
***************************************************************/
#if ANSI_C
struct bwb_line *
bwb_if( struct bwb_line *l )
#else
struct bwb_line *
bwb_if( l )
struct bwb_line *l;
#endif
{
int then, els;
struct exp_ese *e;
int glnumber;
int tpos;
static char tbuf[ MAXSTRINGSIZE + 1 ];
static struct bwb_line gline;
#if STRUCT_CMDS
static struct bwb_line *else_line;
static struct bwb_line *endif_line;
#endif
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in bwb_if(): entry, line <%d> buffer <%s>",
l->number, &( l->buffer[ l->position ] ) );
bwb_debug( bwb_ebuf );
getchar();
#endif
#if INTENSIVE_DEBUG
if ( l == &gline )
{
sprintf( bwb_ebuf, "in bwb_if(): recursive call, l = &gline" );
bwb_debug( bwb_ebuf );
}
#endif
/* Call bwb_exp() to evaluate the condition. This should return
with position set to the "THEN" statement */
e = bwb_exp( l->buffer, FALSE, &( l->position ) );
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in bwb_if(): line <%d> condition returns <%d>",
l->number, exp_getnval( e ) );
bwb_debug( bwb_ebuf );
#endif
/* test for "THEN" and "ELSE" statements */
cnd_thenels( l->buffer, l->position, &then, &els );
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in bwb_if(): return from cnd_thenelse, line is <%s>",
l->buffer );
bwb_debug( bwb_ebuf );
#endif
/* test for multiline IF statement: this presupposes ANSI-compliant
structured BASIC */
#if STRUCT_CMDS
tpos = then + strlen( CMD_THEN ) + 1;
if ( is_eol( l->buffer, &tpos ) == TRUE )
{
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in bwb_if(): found multi-line IF statement, line <%d>",
l->number );
bwb_debug( bwb_ebuf );
#endif
/* find END IF and possibly ELSE[IF] line(s) */
else_line = NULL;
endif_line = find_endif( l, &else_line );
/* evaluate the expression */
if ( (int) exp_getnval( e ) != FALSE )
{
bwb_incexec();
bwb_setexec( l->next, 0, EXEC_IFTRUE );
#if MULTISEG_LINES
adv_eos( l->buffer, &( l->position ));
#endif
return bwb_zline( l );
}
else if ( else_line != NULL )
{
bwb_incexec();
bwb_setexec( else_line, 0, EXEC_IFFALSE );
else_line->position = 0;
return else_line;
}
else
{
bwb_setexec( endif_line, 0, CURTASK excs[ CURTASK exsc ].code );
endif_line->position = 0;
return endif_line;
}
}
#endif /* STRUCT_CMDS for Multi-line IF...THEN */
/* Not a Multi-line IF...THEN: test for THEN line-number */
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in bwb_if(): not multi-line; line is <%s>",
l->buffer );
bwb_debug( bwb_ebuf );
#endif
/* evaluate and execute */
if ( (int) exp_getnval( e ) != FALSE )
{
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in bwb_if(): expression is TRUE" );
bwb_debug( bwb_ebuf );
#endif
if ( then == FALSE )
{
#if PROG_ERRORS
sprintf( bwb_ebuf, "in bwb_if(): IF without THEN" );
bwb_error( bwb_ebuf );
#else
bwb_error( err_syntax );
#endif
}
else
{
/* check for THEN followed by literal line number */
tpos = then + strlen( CMD_THEN ) + 1;
adv_element( l->buffer, &tpos, tbuf );
if ( isdigit( tbuf[ 0 ] ) != 0 )
{
glnumber = atoi( tbuf );
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "Detected THEN followed by line number <%d>",
glnumber );
bwb_debug( bwb_ebuf );
#endif
sprintf( tbuf, "%s %d", CMD_GOTO, glnumber );
gline.buffer = tbuf;
gline.marked = FALSE;
gline.position = 0;
gline.next = l->next;
bwb_setexec( &gline, 0, CURTASK excs[ CURTASK exsc ].code );
return &gline;
}
/* form is not THEN followed by line number */
else
{
bwb_setexec( l, then, CURTASK excs[ CURTASK exsc ].code );
l->position = then + strlen( CMD_THEN ) + 1;
}
return l;
}
}
else
{
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in bwb_if(): expression is FALSE" );
bwb_debug( bwb_ebuf );
#endif
if ( els != FALSE )
{
l->position = els + strlen( CMD_ELSE ) + 1;
bwb_setexec( l, els, EXEC_NORM );
return l;
}
}
/* if neither then nor else were found, advance to next line */
/* DO NOT advance to next segment (only if TRUE should we do that */
l->next->position = 0;
return l->next;
}
/***************************************************************
FUNCTION: cnd_thenelse()
DESCRIPTION: This function searches through the
<buffer> beginning at point <position>
and attempts to find positions of THEN
and ELSE statements.
***************************************************************/
#if ANSI_C
static int
cnd_thenels( char *buffer, int position, int *then, int *els )
#else
static int
cnd_thenels( buffer, position, then, els )
char *buffer;
int position;
int *then;
int *els;
#endif
{
int loop, t_pos, b_pos, p_word;
char tbuf[ MAXSTRINGSIZE + 1 ];
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in cnd_thenels(): entry, line is <%s>",
&( buffer[ position ] ) );
bwb_debug( bwb_ebuf );
#endif
/* set then and els to 0 initially */
*then = *els = 0;
/* loop to find words */
p_word = b_pos = position;
t_pos = 0;
tbuf[ 0 ] = '¥0';
loop = TRUE;
while( loop == TRUE )
{
switch( buffer[ b_pos ] )
{
case '¥0': /* end of string */
case ' ': /* whitespace = end of word */
case '¥t':
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in cnd_thenels(): word is <%s>", tbuf );
bwb_debug( bwb_ebuf );
#endif
if ( strncmp( tbuf, CMD_THEN, (size_t) strlen( CMD_THEN ) ) == 0 )
{
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in cnd_thenels(): THEN found at position <%d>.",
p_word );
bwb_debug( bwb_ebuf );
sprintf( bwb_ebuf, "in cnd_thenelse(): after THEN, line is <%s>", buffer );
bwb_debug( bwb_ebuf );
#endif
*then = p_word;
}
else if ( strncmp( tbuf, CMD_ELSE, (size_t) strlen( CMD_ELSE ) ) == 0 )
{
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in cnd_thenels(): ELSE found at position <%d>.",
p_word );
bwb_debug( bwb_ebuf );
sprintf( bwb_ebuf, "in cnd_thenelse(): after ELSE, line is <%s>", buffer );
bwb_debug( bwb_ebuf );
#endif
*els = p_word;
}
/* check for end of the line */
if ( buffer[ b_pos ] == '¥0' )
{
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in cnd_thenels(): return: end of string" );
bwb_debug( bwb_ebuf );
#endif
return TRUE;
}
++b_pos;
p_word = b_pos;
t_pos = 0;
tbuf[ 0 ] = '¥0';
break;
default:
if ( islower( buffer[ b_pos ] ) != FALSE )
{
tbuf[ t_pos ] = (char) toupper( buffer[ b_pos ] );
}
else
{
tbuf[ t_pos ] = buffer[ b_pos ];
}
++b_pos;
++t_pos;
tbuf[ t_pos ] = '¥0';
break;
}
}
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in cnd_thenelse(): exit, line is <%s>", buffer );
bwb_debug( bwb_ebuf );
#endif
return FALSE;
}
#if STRUCT_CMDS
/***************************************************************
FUNCTION: bwb_else()
DESCRIPTION: This function handles the BASIC ELSE
statement.
SYNTAX: ELSE
***************************************************************/
#if ANSI_C
struct bwb_line *
bwb_else( struct bwb_line *l )
#else
struct bwb_line *
bwb_else( l )
struct bwb_line *l;
#endif
{
struct bwb_line *endif_line;
struct bwb_line *else_line;
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in bwb_else(): entered function" );
bwb_debug( bwb_ebuf );
#endif
/* If the code is EXEC_NORM, then this is a continuation of a single-
line IF...THEN...ELSE... statement and we should return */
if ( CURTASK excs[ CURTASK exsc ].code == EXEC_NORM )
{
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in bwb_else(): detected EXEC_NORM" );
bwb_debug( bwb_ebuf );
#endif
return bwb_zline( l );
}
endif_line = find_endif( l, &else_line );
if ( CURTASK excs[ CURTASK exsc ].code == EXEC_IFTRUE )
{
endif_line->position = 0;
return endif_line;
}
else if ( CURTASK excs[ CURTASK exsc ].code == EXEC_IFFALSE )
{
return bwb_zline( l );
}
#if PROG_ERRORS
sprintf( bwb_ebuf, "in bwb_else(): ELSE without IF" );
bwb_error( bwb_ebuf );
#else
bwb_error( err_syntax );
#endif
return bwb_zline( l );
}
/***************************************************************
FUNCTION: bwb_elseif()
DESCRIPTION: This function handles the BASIC ELSEIF
statement.
SYNTAX: ELSEIF
***************************************************************/
#if ANSI_C
struct bwb_line *
bwb_elseif( struct bwb_line *l )
#else
struct bwb_line *
bwb_elseif( l )
struct bwb_line *l;
#endif
{
struct bwb_line *endif_line;
struct bwb_line *else_line;
struct exp_ese *e;
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in bwb_elseif(): entered function" );
bwb_debug( bwb_ebuf );
#endif
else_line = NULL;
endif_line = find_endif( l, &else_line );
if ( CURTASK excs[ CURTASK exsc ].code == EXEC_IFTRUE )
{
endif_line->position = 0;
return endif_line;
}
else if ( CURTASK excs[ CURTASK exsc ].code == EXEC_IFFALSE )
{
/* Call bwb_exp() to evaluate the condition. This should return
with position set to the "THEN" statement */
e = bwb_exp( l->buffer, FALSE, &( l->position ) );
if ( (int) exp_getnval( e ) == TRUE )
{
/* ELSEIF condition is TRUE: proceed to the next line */
CURTASK excs[ CURTASK exsc ].code = EXEC_IFTRUE;
#if MULTISEG_LINES
adv_eos( l->buffer, &( l->position ));
#endif
return bwb_zline( l );
}
/* ELSEIF condition FALSE: proceed to next ELSE line if there is one */
else if ( else_line != NULL )
{
bwb_setexec( else_line, 0, EXEC_IFFALSE );
else_line->position = 0;
return else_line;
}
/* ELSEIF condition is FALSE and no more ELSExx lines: proceed to END IF */
else
{
bwb_setexec( endif_line, 0, CURTASK excs[ CURTASK exsc ].code );
endif_line->position = 0;
return endif_line;
}
}
#if PROG_ERRORS
sprintf( bwb_ebuf, "in bwb_elseif(): ELSEIF without IF" );
bwb_error( bwb_ebuf );
#else
bwb_error( err_syntax );
#endif
#if MULTISEG_LINES
adv_eos( l->buffer, &( l->position ));
#endif
return bwb_zline( l );
}
/***************************************************************
FUNCTION: bwb_endif()
DESCRIPTION: This function handles the BASIC END IF
statement.
SYNTAX: END IF
***************************************************************/
#if ANSI_C
struct bwb_line *
bwb_endif( struct bwb_line *l )
#else
struct bwb_line *
bwb_endif( l )
struct bwb_line *l;
#endif
{
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in bwb_endif(): entered function" );
bwb_debug( bwb_ebuf );
#endif
if (( CURTASK excs[ CURTASK exsc ].code != EXEC_IFTRUE )
&& ( CURTASK excs[ CURTASK exsc ].code != EXEC_IFFALSE ))
{
#if PROG_ERRORS
sprintf( bwb_ebuf, "in bwb_endif(): END IF without IF" );
bwb_error( bwb_ebuf );
#else
bwb_error( err_syntax );
#endif
}
bwb_decexec();
#if MULTISEG_LINES
adv_eos( l->buffer, &( l->position ));
#endif
return bwb_zline( l );
}
/***************************************************************
FUNCTION: find_endif()
DESCRIPTION: This C function attempts to find an
END IF statement.
***************************************************************/
#if ANSI_C
static struct bwb_line *
find_endif( struct bwb_line *l, struct bwb_line **else_line )
#else
static struct bwb_line *
find_endif( l, else_line )
struct bwb_line *l;
struct bwb_line **else_line;
#endif
{
struct bwb_line *current;
register int i_level;
int position;
*else_line = NULL;
i_level = 1;
for ( current = l->next; current != &CURTASK bwb_end; current = current->next )
{
position = 0;
if ( current->marked != TRUE )
{
line_start( current->buffer, &position, &( current->lnpos ),
&( current->lnum ),
&( current->cmdpos ),
&( current->cmdnum ),
&( current->startpos ) );
}
current->position = current->startpos;
if ( current->cmdnum > -1 )
{
if ( bwb_cmdtable[ current->cmdnum ].vector == bwb_if )
{
++i_level;
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in find_endif(): found IF at line %d, level %d",
current->number, i_level );
bwb_debug( bwb_ebuf );
#endif
}
else if ( is_endif( current ) == TRUE )
{
--i_level;
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in find_endif(): found END IF at line %d, level %d",
current->number, i_level );
bwb_debug( bwb_ebuf );
#endif
if ( i_level == 0 )
{
return current;
}
}
else if ( ( bwb_cmdtable[ current->cmdnum ].vector == bwb_else )
|| ( bwb_cmdtable[ current->cmdnum ].vector == bwb_elseif ))
{
/* we must only report the first ELSE or ELSE IF we encounter
at level 1 */
if ( ( i_level == 1 ) && ( *else_line == NULL ))
{
*else_line = current;
}
}
}
}
#if PROG_ERRORS
sprintf( bwb_ebuf, "Multiline IF without END IF" );
bwb_error( bwb_ebuf );
#else
bwb_error( err_syntax );
#endif
return NULL;
}
/***************************************************************
FUNCTION: is_endif()
DESCRIPTION: This C function attempts to determine if
a given line contains an END IF statement.
***************************************************************/
#if ANSI_C
static int
is_endif( struct bwb_line *l )
#else
static int
is_endif( l )
struct bwb_line *l;
#endif
{
int position;
char tbuf[ MAXVARNAMESIZE + 1];
if ( bwb_cmdtable[ l->cmdnum ].vector != bwb_xend )
{
return FALSE;
}
position = l->startpos;
adv_ws( l->buffer, &position );
adv_element( l->buffer, &position, tbuf );
bwb_strtoupper( tbuf );
if ( strcmp( tbuf, "IF" ) == 0 )
{
return TRUE;
}
return FALSE;
}
/***************************************************************
FUNCTION: bwb_select()
DESCRIPTION: This C function handles the BASIC SELECT
statement.
SYNTAX: SELECT CASE expression
***************************************************************/
#if ANSI_C
struct bwb_line *
bwb_select( struct bwb_line *l )
#else
struct bwb_line *
bwb_select( l )
struct bwb_line *l;
#endif
{
char tbuf[ MAXSTRINGSIZE + 1 ];
struct exp_ese *e;
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in bwb_select(): entered function" );
bwb_debug( bwb_ebuf );
#endif
/* first element should be "CASE" */
adv_element( l->buffer, &( l->position ), tbuf );
bwb_strtoupper( tbuf );
if ( strcmp( tbuf, "CASE" ) != 0 )
{
#if PROG_ERRORS
sprintf( bwb_ebuf, "SELECT without CASE" );
bwb_error( bwb_ebuf );
#else
bwb_error( err_syntax );
return bwb_zline( l );
#endif
}
/* increment the level and set to EXEC_SELFALSE */
bwb_incexec();
CURTASK excs[ CURTASK exsc ].code = EXEC_SELFALSE;
/* evaluate the expression at this level */
e = bwb_exp( l->buffer, FALSE, &( l->position ) );
#if OLDWAY
memcpy( &( CURTASK excs[ CURTASK exsc ].expression ), e,
sizeof( struct exp_ese ) );
#endif
if ( e->type == STRING )
{
CURTASK excs[ CURTASK exsc ].expression.type = STRING;
str_btob( &( CURTASK excs[ CURTASK exsc ].expression.sval ),
&( e->sval ) );
}
else
{
CURTASK excs[ CURTASK exsc ].expression.type = NUMBER;
CURTASK excs[ CURTASK exsc ].expression.nval
= exp_getnval( e );
}
/* return */
#if MULTISEG_LINES
adv_eos( l->buffer, &( l->position ));
#endif
return bwb_zline( l );
}
/***************************************************************
FUNCTION: bwb_case()
DESCRIPTION: This C function handles the BASIC CASE
statement.
SYNTAX: CASE constant | IF partial-expression | ELSE
***************************************************************/
#if ANSI_C
struct bwb_line *
bwb_case( struct bwb_line *l )
#else
struct bwb_line *
bwb_case( l )
struct bwb_line *l;
#endif
{
char tbuf[ MAXSTRINGSIZE + 1 ];
int oldpos;
struct exp_ese minvalue;
struct exp_ese *maxval, *minval;
struct bwb_line *retline;
char cbuf1[ MAXSTRINGSIZE + 1 ];
char cbuf2[ MAXSTRINGSIZE + 1 ];
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in bwb_case(): entered function" );
bwb_debug( bwb_ebuf );
#endif
/* if code is EXEC_SELTRUE, then we should jump to the end */
if ( CURTASK excs[ CURTASK exsc ].code == EXEC_SELTRUE )
{
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in bwb_case(): exit EXEC_SELTRUE" );
bwb_debug( bwb_ebuf );
#endif
retline = find_endselect( l );
retline->position = 0;
return retline;
}
/* read first element */
oldpos = l->position;
adv_element( l->buffer, &( l->position ), tbuf );
bwb_strtoupper( tbuf );
/* check for CASE IF */
if ( strcmp( tbuf, CMD_IF ) == 0 )
{
return bwb_caseif( l );
}
/* check for CASE ELSE: if true, simply proceed to the next line,
because other options should have been detected by now */
else if ( strcmp( tbuf, CMD_ELSE ) == 0 )
{
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in bwb_case(): execute CASE ELSE" );
bwb_debug( bwb_ebuf );
#endif
return bwb_zline( l );
}
/* neither CASE ELSE nor CASE IF; presume constant here for min value */
l->position = oldpos;
minval = bwb_exp( l->buffer, FALSE, &( l->position ));
memcpy( &minvalue, minval, sizeof( struct exp_ese ) );
maxval = minval = &minvalue;
/* check for string value */
if ( minvalue.type == STRING )
{
str_btoc( cbuf1, &( CURTASK excs[ CURTASK exsc ].expression.sval ) );
str_btoc( cbuf2, &( minvalue.sval ) );
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in bwb_case(): compare strings <%s> and <%s>",
cbuf1, cbuf2 );
bwb_debug( bwb_ebuf );
#endif
if ( strncmp( cbuf1, cbuf2, MAXSTRINGSIZE ) == 0 )
{
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in bwb_case(): string comparison returns TRUE" );
bwb_debug( bwb_ebuf );
#endif
CURTASK excs[ CURTASK exsc ].code = EXEC_SELTRUE;
#if MULTISEG_LINES
adv_eos( l->buffer, &( l->position ));
#endif
return bwb_zline( l );
}
else
{
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in bwb_case(): string comparison returns FALSE" );
bwb_debug( bwb_ebuf );
#endif
retline = find_case( l );
retline->position = 0;
return retline;
}
}
/* not a string; advance */
adv_ws( l->buffer, &( l->position ));
/* check for TO */
if ( is_eol( l->buffer, &( l->position )) != TRUE )
{
/* find the TO statement */
adv_element( l->buffer, &( l->position ), tbuf );
bwb_strtoupper( tbuf );
if ( strcmp( tbuf, CMD_TO ) != 0 )
{
#if PROG_ERRORS
sprintf( bwb_ebuf, "CASE has inexplicable code following expression" );
bwb_error( bwb_ebuf );
#else
bwb_error( err_syntax );
#if MULTISEG_LINES
adv_eos( l->buffer, &( l->position ));
#endif
return bwb_zline( l );
#endif
}
/* now evaluate the MAX expression */
maxval = bwb_exp( l->buffer, FALSE, &( l->position ));
}
/* evaluate the expression */
if ( case_eval( &( CURTASK excs[ CURTASK exsc ].expression ),
minval, maxval ) == TRUE )
{
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in bwb_case(): evaluation returns TRUE" );
bwb_debug( bwb_ebuf );
#endif
CURTASK excs[ CURTASK exsc ].code = EXEC_SELTRUE;
#if MULTISEG_LINES
adv_eos( l->buffer, &( l->position ));
#endif
return bwb_zline( l );
}
/* evaluation returns a FALSE value; find next CASE or END SELECT statement */
else
{
#if INTENSIVE_DEBUGb
sprintf( bwb_ebuf, "in bwb_case(): evaluation returns FALSE" );
bwb_debug( bwb_ebuf );
#endif
retline = find_case( l );
retline->position = 0;
return retline;
}
}
/***************************************************************
FUNCTION: bwb_caseif()
DESCRIPTION: This C function handles the BASIC CASE IF
statement.
***************************************************************/
#if ANSI_C
static struct bwb_line *
bwb_caseif( struct bwb_line *l )
#else
static struct bwb_line *
bwb_caseif( l )
struct bwb_line *l;
#endif
{
char tbuf[ MAXSTRINGSIZE + 1 ];
int position;
struct exp_ese *r;
struct bwb_line *retline;
if ( CURTASK excs[ CURTASK exsc ].expression.type == NUMBER )
{
sprintf( tbuf, "%f %s",
(float) CURTASK excs[ CURTASK exsc ].expression.nval,
&( l->buffer[ l->position ] ) );
}
else
{
bwb_error( err_mismatch );
#if MULTISEG_LINES
adv_eos( l->buffer, &( l->position ));
#endif
return bwb_zline( l );
}
position = 0;
r = bwb_exp( tbuf, FALSE, &position );
if ( r->nval == (bnumber) TRUE )
{
CURTASK excs[ CURTASK exsc ].code = EXEC_SELTRUE;
#if MULTISEG_LINES
adv_eos( l->buffer, &( l->position ));
#endif
return bwb_zline( l );
}
else
{
retline = find_case( l );
retline->position = 0;
return retline;
}
}
/***************************************************************
FUNCTION: case_eval()
DESCRIPTION: This function evaluates a case statement
by comparing minimum and maximum values
with a set expression. It returns either
TRUE or FALSE
***************************************************************/
#if ANSI_C
static int
case_eval( struct exp_ese *expression, struct exp_ese *minval,
struct exp_ese *maxval )
#else
static int
case_eval( expression, minval, maxval )
struct exp_ese *expression;
struct exp_ese *minval;
struct exp_ese *maxval;
#endif
{
/* string value */
if ( expression->type == STRING )
{
bwb_error( err_mismatch );
return FALSE;
}
/* numerical value */
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in case_eval(): n <%f> min <%f> max <%f>",
(float) expression->nval,
(float) minval->nval,
(float) maxval->nval );
bwb_debug( bwb_ebuf );
#endif
if ( ( expression->nval >= minval->nval )
&& ( expression->nval <= maxval->nval ))
{
return TRUE;
}
return FALSE;
}
/***************************************************************
FUNCTION: find_case()
DESCRIPTION: This function searches for a line containing
a CASE statement corresponding to a previous
SELECT CASE statement.
***************************************************************/
#if ANSI_C
static struct bwb_line *
find_case( struct bwb_line *l )
#else
static struct bwb_line *
find_case( l )
struct bwb_line *l;
#endif
{
struct bwb_line *current;
register int c_level;
int position;
c_level = 1;
for ( current = l->next; current != &CURTASK bwb_end; current = current->next )
{
position = 0;
if ( current->marked != TRUE )
{
line_start( current->buffer, &position, &( current->lnpos ),
&( current->lnum ),
&( current->cmdpos ),
&( current->cmdnum ),
&( current->startpos ) );
}
current->position = current->startpos;
if ( current->cmdnum > -1 )
{
if ( bwb_cmdtable[ current->cmdnum ].vector == bwb_select )
{
++c_level;
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in find_case(): found SELECT at line %d, level %d",
current->number, c_level );
bwb_debug( bwb_ebuf );
#endif
}
else if ( is_endselect( current ) == TRUE )
{
--c_level;
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in find_endif(): found END SELECT at line %d, level %d",
current->number, c_level );
bwb_debug( bwb_ebuf );
#endif
if ( c_level == 0 )
{
return current;
}
}
else if ( bwb_cmdtable[ current->cmdnum ].vector == bwb_case )
{
--c_level;
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in find_case(): found CASE at line %d, level %d",
current->number, c_level );
bwb_debug( bwb_ebuf );
#endif
if ( c_level == 0 )
{
return current;
}
}
}
}
#if PROG_ERRORS
sprintf( bwb_ebuf, "SELECT without CASE" );
bwb_error( bwb_ebuf );
#else
bwb_error( err_syntax );
#endif
return NULL;
}
/***************************************************************
FUNCTION: find_case()
DESCRIPTION: This function searches for a line containing
an END SELECT statement corresponding to a previous
SELECT CASE statement.
***************************************************************/
#if ANSI_C
static struct bwb_line *
find_endselect( struct bwb_line *l )
#else
static struct bwb_line *
find_endselect( l )
struct bwb_line *l;
#endif
{
struct bwb_line *current;
register int c_level;
int position;
c_level = 1;
for ( current = l->next; current != &CURTASK bwb_end; current = current->next )
{
position = 0;
if ( current->marked != TRUE )
{
line_start( current->buffer, &position, &( current->lnpos ),
&( current->lnum ),
&( current->cmdpos ),
&( current->cmdnum ),
&( current->startpos ) );
}
current->position = current->startpos;
if ( current->cmdnum > -1 )
{
if ( bwb_cmdtable[ current->cmdnum ].vector == bwb_select )
{
++c_level;
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in find_case(): found SELECT at line %d, level %d",
current->number, c_level );
bwb_debug( bwb_ebuf );
#endif
}
else if ( is_endselect( current ) == TRUE )
{
--c_level;
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in find_endif(): found END SELECT at line %d, level %d",
current->number, c_level );
bwb_debug( bwb_ebuf );
#endif
if ( c_level == 0 )
{
return current;
}
}
}
}
#if PROG_ERRORS
sprintf( bwb_ebuf, "SELECT without END SELECT" );
bwb_error( bwb_ebuf );
#else
bwb_error( err_syntax );
#endif
return NULL;
}
/***************************************************************
FUNCTION: is_endselect()
DESCRIPTION: This C function attempts to determine if
a given line contains an END SELECT statement.
***************************************************************/
#if ANSI_C
static int
is_endselect( struct bwb_line *l )
#else
static int
is_endselect( l )
struct bwb_line *l;
#endif
{
int position;
char tbuf[ MAXVARNAMESIZE + 1];
if ( bwb_cmdtable[ l->cmdnum ].vector != bwb_xend )
{
return FALSE;
}
position = l->startpos;
adv_ws( l->buffer, &position );
adv_element( l->buffer, &position, tbuf );
bwb_strtoupper( tbuf );
if ( strcmp( tbuf, "SELECT" ) == 0 )
{
return TRUE;
}
return FALSE;
}
/***************************************************************
FUNCTION: bwb_endselect()
DESCRIPTION: This function handles the BASIC END
SELECT statement.
SYNTAX: END SELECT
***************************************************************/
#if ANSI_C
struct bwb_line *
bwb_endselect( struct bwb_line *l )
#else
struct bwb_line *
bwb_endselect( l )
struct bwb_line *l;
#endif
{
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in bwb_endselect(): entered function" );
bwb_debug( bwb_ebuf );
#endif
if ( ( CURTASK excs[ CURTASK exsc ].code != EXEC_SELTRUE )
&& ( CURTASK excs[ CURTASK exsc ].code != EXEC_SELFALSE ))
{
#if PROG_ERRORS
sprintf( bwb_ebuf, "in bwb_endselect(): END SELECT without SELECT" );
bwb_error( bwb_ebuf );
#else
bwb_error( err_syntax );
#endif
}
bwb_decexec();
#if MULTISEG_LINES
adv_eos( l->buffer, &( l->position ));
#endif
return bwb_zline( l );
}
#endif /* STRUCT_CMDS */
#if COMMON_CMDS || STRUCT_CMDS
/*** WHILE-WEND ***/
/***************************************************************
FUNCTION: bwb_while()
DESCRIPTION: This function handles the BASIC WHILE
statement and also the ANSI DO WHILE
statement.
SYNTAX: WHILE expression
DO WHILE expression
***************************************************************/
#if ANSI_C
struct bwb_line *
bwb_while( struct bwb_line *l )
#else
struct bwb_line *
bwb_while( l )
struct bwb_line *l;
#endif
{
struct exp_ese *e;
struct bwb_line *r;
/* call bwb_exp() to interpret the expression */
e = bwb_exp( l->buffer, FALSE, &( l->position ) );
if ( (int) exp_getnval( e ) == TRUE )
{
/* if this is the first time at this WHILE statement, note it */
if ( CURTASK excs[ CURTASK exsc ].while_line != l )
{
bwb_incexec();
CURTASK excs[ CURTASK exsc ].while_line = l;
/* find the WEND statement (or LOOP statement) */
#if STRUCT_CMDS
if ( l->cmdnum == getcmdnum( CMD_DO ))
{
CURTASK excs[ CURTASK exsc ].wend_line = find_loop( l );
}
else
{
CURTASK excs[ CURTASK exsc ].wend_line = find_wend( l );
}
#else
CURTASK excs[ CURTASK exsc ].wend_line = find_wend( l );
#endif
if ( CURTASK excs[ CURTASK exsc ].wend_line == NULL )
{
return bwb_zline( l );
}
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in bwb_while(): initialize WHILE loop, line <%d>",
l->number );
bwb_debug( bwb_ebuf );
#endif
}
#if INTENSIVE_DEBUG
else
{
sprintf( bwb_ebuf, "in bwb_while(): return to WHILE loop, line <%d>",
l->number );
bwb_debug( bwb_ebuf );
}
#endif
bwb_setexec( l, l->position, EXEC_WHILE );
return bwb_zline( l );
}
else
{
CURTASK excs[ CURTASK exsc ].while_line = NULL;
r = CURTASK excs[ CURTASK exsc ].wend_line;
bwb_setexec( r, 0, CURTASK excs[ CURTASK exsc - 1 ].code );
r->position = 0;
bwb_decexec();
return r;
}
}
/***************************************************************
FUNCTION: bwb_wend()
DESCRIPTION: This function handles the BASIC WEND
statement and the LOOP statement ending
a DO WHILE loop.
SYNTAX: WEND
LOOP
***************************************************************/
#if ANSI_C
struct bwb_line *
bwb_wend( struct bwb_line *l )
#else
struct bwb_line *
bwb_wend( l )
struct bwb_line *l;
#endif
{
/* check integrity of WHILE loop */
if ( CURTASK excs[ CURTASK exsc ].code != EXEC_WHILE )
{
#if PROG_ERRORS
sprintf( bwb_ebuf, "in bwb_wend(): exec stack code != EXEC_WHILE" );
bwb_error( bwb_ebuf );
#else
bwb_error( err_syntax );
#endif
}
if ( CURTASK excs[ CURTASK exsc ].while_line == NULL )
{
#if PROG_ERRORS
sprintf( bwb_ebuf, "in bwb_wend(): exec stack while_line == NULL" );
bwb_error( bwb_ebuf );
#else
bwb_error( err_syntax );
#endif
}
/* reset to the top of the current WHILE loop */
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in bwb_wend() return to line <%d>",
CURTASK excs[ CURTASK exsc ].while_line->number );
bwb_debug( bwb_ebuf );
#endif
CURTASK excs[ CURTASK exsc ].while_line->position = 0;
bwb_setexec( CURTASK excs[ CURTASK exsc ].while_line, 0, EXEC_WHILE );
return CURTASK excs[ CURTASK exsc ].while_line;
}
/***************************************************************
FUNCTION: find_wend()
DESCRIPTION: This function searches for a line containing
a WEND statement corresponding to a previous
WHILE statement.
***************************************************************/
#if ANSI_C
static struct bwb_line *
find_wend( struct bwb_line *l )
#else
static struct bwb_line *
find_wend( l )
struct bwb_line *l;
#endif
{
struct bwb_line *current;
register int w_level;
int position;
w_level = 1;
for ( current = l->next; current != &CURTASK bwb_end; current = current->next )
{
position = 0;
if ( current->marked != TRUE )
{
line_start( current->buffer, &position, &( current->lnpos ),
&( current->lnum ),
&( current->cmdpos ),
&( current->cmdnum ),
&( current->startpos ) );
}
current->position = current->startpos;
if ( current->cmdnum > -1 )
{
if ( bwb_cmdtable[ current->cmdnum ].vector == bwb_while )
{
++w_level;
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in find_wend(): found WHILE at line %d, level %d",
current->number, w_level );
bwb_debug( bwb_ebuf );
#endif
}
else if ( bwb_cmdtable[ current->cmdnum ].vector == bwb_wend )
{
--w_level;
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in find_wend(): found WEND at line %d, level %d",
current->number, w_level );
bwb_debug( bwb_ebuf );
#endif
if ( w_level == 0 )
{
return current->next;
}
}
}
}
#if PROG_ERRORS
sprintf( bwb_ebuf, "in find_wend(): WHILE without WEND" );
bwb_error( bwb_ebuf );
#else
bwb_error( err_syntax );
#endif
return NULL;
}
#if STRUCT_CMDS
/***************************************************************
FUNCTION: find_loop()
DESCRIPTION: This function searches for a line containing
a LOOP statement corresponding to a previous
DO statement.
***************************************************************/
#if ANSI_C
extern struct bwb_line *
find_loop( struct bwb_line *l )
#else
extern struct bwb_line *
find_loop( l )
struct bwb_line *l;
#endif
{
struct bwb_line *current;
register int w_level;
int position;
w_level = 1;
for ( current = l->next; current != &CURTASK bwb_end; current = current->next )
{
position = 0;
if ( current->marked != TRUE )
{
line_start( current->buffer, &position, &( current->lnpos ),
&( current->lnum ),
&( current->cmdpos ),
&( current->cmdnum ),
&( current->startpos ) );
}
current->position = current->startpos;
if ( current->cmdnum > -1 )
{
if ( bwb_cmdtable[ current->cmdnum ].vector == bwb_do )
{
++w_level;
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in find_loop(): found DO at line %d, level %d",
current->number, w_level );
bwb_debug( bwb_ebuf );
#endif
}
else if ( bwb_cmdtable[ current->cmdnum ].vector == bwb_loop )
{
--w_level;
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in fnd_loop(): found LOOP at line %d, level %d",
current->number, w_level );
bwb_debug( bwb_ebuf );
#endif
if ( w_level == 0 )
{
return current->next;
}
}
}
}
#if PROG_ERRORS
sprintf( bwb_ebuf, "in find_loop(): DO without LOOP" );
bwb_error( bwb_ebuf );
#else
bwb_error( err_syntax );
#endif
return NULL;
}
#endif /* STRUCT_CMDS */
#endif /* COMMON_CMDS || STRUCT_CMDS */
/*** FOR-NEXT ***/
/***************************************************************
FUNCTION: bwb_for()
DESCRIPTION: This function handles the BASIC FOR
statement.
SYNTAX: FOR counter = start TO finish [STEP increment]
***************************************************************/
#if ANSI_C
struct bwb_line *
bwb_for( struct bwb_line *l )
#else
struct bwb_line *
bwb_for( l )
struct bwb_line *l;
#endif
{
register int n;
int e, loop;
int to, step, p;
int for_step, for_target;
struct exp_ese *exp;
struct bwb_variable *v;
char tbuf[ MAXSTRINGSIZE + 1 ];
/* get the variable name */
exp_getvfname( &( l->buffer[ l->position ] ), tbuf );
l->position += strlen( tbuf );
v = var_find( tbuf );
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in bwb_for(): variable name <%s>.", v->name );
bwb_debug( bwb_ebuf );
#endif
/* at this point one should find an equals sign ('=') */
adv_ws( l->buffer, &( l->position ) );
if ( l->buffer[ l->position ] != '=' )
{
#if PROG_ERRORS
sprintf( bwb_ebuf, "in bwb_for(): failed to find equals sign, buf <%s>",
&( l->buffer[ l->position ] ) );
bwb_error( bwb_ebuf );
#else
bwb_error( err_syntax );
#endif
return bwb_zline( l );
}
else
{
++( l->position );
}
/* Find the TO and STEP statements */
cnd_tostep( l->buffer, l->position, &to, &step );
/* if there is no TO statement, then an error has ocurred */
if ( to < 1 )
{
#if PROG_ERRORS
sprintf( bwb_ebuf, "FOR statement without TO" );
bwb_error( bwb_ebuf );
#else
bwb_error( err_syntax );
#endif
return bwb_zline( l );
}
/* copy initial value to buffer and evaluate it */
tbuf[ 0 ] = '¥0';
p = 0;
for ( n = l->position; n < to; ++n )
{
tbuf[ p ] = l->buffer[ n ];
++p;
++l->position;
tbuf[ p ] = '¥0';
}
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in bwb_for(): initial value string <%s>",
tbuf );
bwb_debug( bwb_ebuf );
#endif
p = 0;
exp = bwb_exp( tbuf, FALSE, &p );
var_setnval( v, exp_getnval( exp ) );
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in bwb_for(): initial value <%d> pos <%d>",
exp_getnval( exp ), l->position );
bwb_debug( bwb_ebuf );
#endif
/* copy target value to small buffer and evaluate it */
tbuf[ 0 ] = '¥0';
p = 0;
l->position = to + 2;
if ( step < 1 )
{
e = strlen( l->buffer );
}
else
{
e = step - 1;
}
loop = TRUE;
n = l->position;
while( loop == TRUE )
{
tbuf[ p ] = l->buffer[ n ];
++p;
++l->position;
tbuf[ p ] = '¥0';
if ( n >= e )
{
loop = FALSE;
}
++n;
if ( l->buffer[ n ] == ':' )
{
loop = FALSE;
}
}
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in bwb_for(): target value string <%s>",
tbuf );
bwb_debug( bwb_ebuf );
#endif
p = 0;
exp = bwb_exp( tbuf, FALSE, &p );
for_target = (int) exp_getnval( exp );
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in bwb_for(): target value <%d> pos <%d>",
exp_getnval( exp ), l->position );
bwb_debug( bwb_ebuf );
#endif
/* If there is a STEP statement, copy it to a buffer
and evaluate it */
if ( step > 1 )
{
tbuf[ 0 ] = '¥0';
p = 0;
l->position = step + 4;
for ( n = l->position; n < (int) strlen( l->buffer ); ++n )
{
tbuf[ p ] = l->buffer[ n ];
++p;
++l->position;
tbuf[ p ] = '¥0';
}
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in bwb_for(): step value string <%s>",
tbuf );
bwb_debug( bwb_ebuf );
#endif
p = 0;
exp = bwb_exp( tbuf, FALSE, &p );
for_step = (int) exp_getnval( exp );
}
else
{
for_step = 1;
}
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in bwb_for(): step value <%d>",
for_step );
bwb_debug( bwb_ebuf );
#endif
/* set position in current line and increment EXEC counter */
/* bwb_setexec( l, l->position, EXEC_NORM ); */ /* WRONG */
bwb_incexec();
CURTASK excs[ CURTASK exsc ].local_variable = v;
CURTASK excs[ CURTASK exsc ].for_step = for_step;
CURTASK excs[ CURTASK exsc ].for_target = for_target;
/* set exit line to be used by EXIT FOR */
#if STRUCT_CMDS
CURTASK excs[ CURTASK exsc ].wend_line = find_next( l );
#endif
/* set top line and position to be used in multisegmented FOR-NEXT loop */
#if MULTISEG_LINES
CURTASK excs[ CURTASK exsc ].for_line = l;
CURTASK excs[ CURTASK exsc ].for_position = l->position;
#endif
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in bwb_for(): setting code to EXEC_FOR",
l->position );
bwb_debug( bwb_ebuf );
#endif
bwb_setexec( l, l->position, EXEC_FOR );
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in bwb_for(): ready to exit, position <%d>",
l->position );
bwb_debug( bwb_ebuf );
#endif
/* proceed with processing */
return bwb_zline( l );
}
/***************************************************************
FUNCTION: bwb_next()
DESCRIPTION: This function handles the BASIC NEXT
statement.
SYNTAX: NEXT counter
***************************************************************/
#if ANSI_C
struct bwb_line *
bwb_next( struct bwb_line *l )
#else
struct bwb_line *
bwb_next( l )
struct bwb_line *l;
#endif
{
char tbuf[ MAXSTRINGSIZE + 1 ];
#if INTENSIVE_DEBUG
struct bwb_variable *v;
#endif
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in bwb_next(): entered function, cmdnum <%d> exsc level <%d> code <%d>",
l->cmdnum, CURTASK exsc, CURTASK excs[ CURTASK exsc ].code );
bwb_debug( bwb_ebuf );
#endif
/* Check the integrity of the FOR statement */
if ( CURTASK excs[ CURTASK exsc ].code != EXEC_FOR )
{
#if PROG_ERRORS
sprintf( bwb_ebuf, "in bwb_next(): NEXT without FOR; code is <%d> instead of <%d>",
CURTASK excs[ CURTASK exsc ].code, EXEC_FOR );
bwb_error( bwb_ebuf );
#else
bwb_error( err_syntax );
#endif
}
/* read the argument, if there is one */
#if MULTISEG_LINES /* not currently needed otherwise */
exp_getvfname( &( l->buffer[ l->position ] ), tbuf );
l->position += strlen( tbuf );
#if INTENSIVE_DEBUG
v = var_find( tbuf );
sprintf( bwb_ebuf, "in bwb_next(): variable name detected <%s>.", v->name );
bwb_debug( bwb_ebuf );
#endif
#endif
/* decrement or increment the value */
var_setnval( CURTASK excs[ CURTASK exsc ].local_variable,
var_getnval( CURTASK excs[ CURTASK exsc ].local_variable )
+ (bnumber) CURTASK excs[ CURTASK exsc ].for_step );
/* check for completion of the loop */
if ( CURTASK excs[ CURTASK exsc ].for_step > 0 ) /* if step is positive */
{
if ( (int) var_getnval( CURTASK excs[ CURTASK exsc ].local_variable )
> CURTASK excs[ CURTASK exsc ].for_target )
{
bwb_decexec();
#if MULTISEG_LINES
bwb_setexec( l, l->position, CURTASK excs[ CURTASK exsc ].code );
#else
bwb_setexec( l->next, 0, CURTASK excs[ CURTASK exsc ].code );
#endif
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in bwb_next(): end of loop" );
bwb_debug( bwb_ebuf );
#endif
#ifdef OLD_WAY
l->next->position = 0;
return l->next;
#else
return bwb_zline( l );
#endif
}
}
else /* if step is negative */
{
if ( (int) var_getnval( CURTASK excs[ CURTASK exsc ].local_variable )
< CURTASK excs[ CURTASK exsc ].for_target )
{
bwb_decexec();
bwb_setexec( l->next, 0, CURTASK excs[ CURTASK exsc ].code );
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in bwb_next(): end of loop" );
bwb_debug( bwb_ebuf );
#endif
#ifdef OLD_WAY
l->next->position = 0;
return l->next;
#else
return bwb_zline( l );
#endif
}
}
/* Target not reached: return to the top of the FOR loop */
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in bwb_next(): resetting code to EXEC_FOR",
l->position );
bwb_debug( bwb_ebuf );
#endif
#if MULTISEG_LINES
CURTASK excs[ CURTASK exsc ].for_line->position
= CURTASK excs[ CURTASK exsc ].for_position;
bwb_setexec( CURTASK excs[ CURTASK exsc ].for_line,
CURTASK excs[ CURTASK exsc ].for_position, EXEC_FOR );
#else
bwb_setexec( CURTASK excs[ CURTASK exsc - 1 ].line,
CURTASK excs[ CURTASK exsc - 1 ].position, EXEC_FOR );
#endif
return CURTASK excs[ CURTASK exsc - 1 ].line;
}
#if STRUCT_CMDS
/***************************************************************
FUNCTION: bwb_exitfor()
DESCRIPTION: This function handles the BASIC EXIT
FOR statement. This is a structured
programming command compatible with ANSI
BASIC. It is called from the bwb_exit()
subroutine.
SYNTAX: EXIT FOR
***************************************************************/
#if ANSI_C
struct bwb_line *
bwb_exitfor( struct bwb_line *l )
#else
struct bwb_line *
bwb_exitfor( l )
struct bwb_line *l;
#endif
{
struct bwb_line *next_line;
int found;
register int level;
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in bwb_exitfor(): entered subroutine" );
bwb_debug( bwb_ebuf );
#endif
/* Check the integrity of the FOR statement */
found = FALSE;
level = CURTASK exsc;
do
{
if ( CURTASK excs[ level ].code == EXEC_FOR )
{
next_line = CURTASK excs[ CURTASK level ].wend_line;
found = TRUE;
}
else
{
--level;
}
}
while ( ( level >= 0 ) && ( found == FALSE ) );
if ( found != TRUE )
{
#if PROG_ERRORS
sprintf( bwb_ebuf, "in bwb_exitfor(): EXIT FOR without FOR" );
bwb_error( bwb_ebuf );
#else
bwb_error( err_syntax );
#endif
return bwb_zline( l );
}
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in bwb_exitfor(): level found is <%d>, current <%d>",
level, CURTASK exsc );
bwb_debug( bwb_ebuf );
#endif
/* decrement below the level of the NEXT statement */
while( CURTASK exsc >= level )
{
bwb_decexec();
}
/* set the next line in the exec stack */
next_line->position = 0;
bwb_setexec( next_line, 0, EXEC_NORM );
return next_line;
}
/***************************************************************
FUNCTION: find_next()
DESCRIPTION: This function searches for a line containing
a NEXT statement corresponding to a previous
FOR statement.
***************************************************************/
#if ANSI_C
static struct bwb_line *
find_next( struct bwb_line *l )
#else
static struct bwb_line *
find_next( l )
struct bwb_line *l;
#endif
{
struct bwb_line *current;
register int w_level;
int position;
w_level = 1;
for ( current = l->next; current != &CURTASK bwb_end; current = current->next )
{
position = 0;
if ( current->marked != TRUE )
{
line_start( current->buffer, &position, &( current->lnpos ),
&( current->lnum ),
&( current->cmdpos ),
&( current->cmdnum ),
&( current->startpos ) );
}
current->position = current->startpos;
if ( current->cmdnum > -1 )
{
if ( bwb_cmdtable[ current->cmdnum ].vector == bwb_for )
{
++w_level;
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in find_next(): found FOR at line %d, level %d",
current->number, w_level );
bwb_debug( bwb_ebuf );
#endif
}
else if ( bwb_cmdtable[ current->cmdnum ].vector == bwb_next )
{
--w_level;
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in find_next(): found NEXT at line %d, level %d",
current->number, w_level );
bwb_debug( bwb_ebuf );
#endif
if ( w_level == 0 )
{
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in find_next(): found returning line <%d>",
current->next->number );
bwb_debug( bwb_ebuf );
#endif
return current->next;
}
}
}
}
#if PROG_ERRORS
sprintf( bwb_ebuf, "FOR without NEXT" );
bwb_error( bwb_ebuf );
#else
bwb_error( err_syntax );
#endif
return NULL;
}
#endif /* STRUCT_CMDS for EXIT FOR */
/***************************************************************
FUNCTION: cnd_tostep()
DESCRIPTION: This function searches through the
<buffer> beginning at point <position>
and attempts to find positions of TO
and STEP statements.
***************************************************************/
#if ANSI_C
static int
cnd_tostep( char *buffer, int position, int *to, int *step )
#else
static int
cnd_tostep( buffer, position, to, step )
char *buffer;
int position;
int *to;
int *step;
#endif
{
int loop, t_pos, b_pos, p_word;
char tbuf[ MAXSTRINGSIZE + 1 ];
/* set then and els to FALSE initially */
*to = *step = FALSE;
/* loop to find words */
p_word = b_pos = position;
t_pos = 0;
tbuf[ 0 ] = '¥0';
loop = TRUE;
while ( loop == TRUE )
{
switch( buffer[ b_pos ] )
{
case '¥0': /* end of string */
case ':': /* end of line segment */
return TRUE;
case ' ': /* whitespace = end of word */
case '¥t':
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in cnd_tostep(): word is <%s>", tbuf );
bwb_debug( bwb_ebuf );
#endif
if ( strncmp( tbuf, CMD_TO, (size_t) strlen( CMD_TO ) ) == 0 )
{
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in cnd_tostep(): TO found at position <%d>.",
p_word );
bwb_debug( bwb_ebuf );
#endif
*to = p_word;
}
else if ( strncmp( tbuf, CMD_STEP, (size_t) strlen( CMD_STEP ) ) == 0 )
{
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in cnd_tostep(): STEP found at position <%d>.",
p_word );
bwb_debug( bwb_ebuf );
#endif
*step = p_word;
}
++b_pos;
p_word = b_pos;
t_pos = 0;
tbuf[ 0 ] = '¥0';
break;
default:
if ( islower( buffer[ b_pos ] ) != FALSE )
{
tbuf[ t_pos ] = (char) toupper( buffer[ b_pos ] );
}
else
{
tbuf[ t_pos ] = buffer[ b_pos ];
}
++b_pos;
++t_pos;
tbuf[ t_pos ] = '¥0';
break;
}
}
return TRUE;
}
/***************************************************************
FUNCTION: var_setnval()
DESCRIPTION: This function sets the value of numerical
variable v to the value of i.
***************************************************************/
#if ANSI_C
extern int
var_setnval( struct bwb_variable *v, bnumber i )
#else
int
var_setnval( v, i )
struct bwb_variable *v;
bnumber i;
#endif
{
switch( v->type )
{
case NUMBER:
* var_findnval( v, v->array_pos ) = i;
break;
default:
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in var_setnval(): variable <%s> is not a number",
v->name );
bwb_error( bwb_ebuf );
#else
bwb_error( err_mismatch );
#endif
}
/* successful assignment */
return TRUE;
}