on_proc.c

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/*****************************************************************************
 * ugBASIC - an isomorphic BASIC language compiler for retrocomputers        *
 *****************************************************************************
 * Copyright 2021-2026 Marco Spedaletti (asimov@mclink.it)
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
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 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *----------------------------------------------------------------------------
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 * (la "Licenza"); è proibito usare questo file se non in conformità alla
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/****************************************************************************
 * INCLUDE SECTION 
 ****************************************************************************/
 
#include "../../ugbc.h"
 
/****************************************************************************
 * CODE SECTION 
 ****************************************************************************/

/* <usermanual>
@keyword ON...PROC
 
@english
This command is used to force a call to subroutine when a 
specific expression is calculated. The choice is done against several positions,
and it depends on what value is held by the expression at the time it is spotted.
 
To work properly, the expression must have a value from 1 up to the number of 
the highest possible destination. If the expression has a value of 0 or 
greater than the highest possibile destination, no call will be performed.
 
Important: if the ''OPTION CALL AS GOTO'' pragma is in effect, the instruction
will be considered as a ''GOTO'' rather than a ''GOSUB''. So, no return value and
no return, at all. This not applies to system calls.
 
@italian
Questo comando viene utilizzato per forzare una chiamata a subroutine,
calcolata da un'espressione. La scelta è tra le posizioni
elencate, e dipende dal valore dell'espressione al momento in cui viene 
calcolata.
 
Per funzionare correttamente, l'espressione deve avere un valore compreso 
tra 1 e il numero di destinazioni. Se l'espressione ha un valore di 0 o
maggiore della destinazione più alta possibile, non sarà eseguito alcun salto.
 
Importante: se il pragma ''OPTION CALL AS GOTO'' è attivo, l'istruzione
sarà considerata un ''GOTO'' piuttosto che un ''GOSUB''. Quindi, nessun
valore di ritorno e, anzi, nessun ritorno sarà previsto. Questo non si applica
alle chiamate di sistema.
 
@syntax ON expression PROC name1[, name2 [, ... ] ]
 
@example ON level PROC level1, level2, level3
@usedInExample procedures_jumping_01.bas
 
@target all
</usermanual> */
void on_proc( Environment * _environment, char * _expression ) {
 
    MAKE_LABEL
 
    Variable * expression = variable_retrieve( _environment, _expression );
 
    char newLabel[MAX_TEMPORARY_STORAGE]; sprintf(newLabel, "proc%d", UNIQUE_ID );
 
    Conditional * conditional = malloc( sizeof( Conditional ) );
    conditional->label = strdup( newLabel );
    conditional->type = CT_ON_PROC;
    conditional->expression = variable_cast( _environment, expression->name, expression->type );
    conditional->expression->locked = 1;
    conditional->index = 1;
    conditional->next = _environment->conditionals;
    _environment->conditionals = conditional;
 
}

void on_proc_index( Environment * _environment, char * _label ) {
 
    Conditional * conditional = _environment->conditionals;
 
    if ( ! conditional ) {
        CRITICAL_INTERNAL_ERROR("on_proc_index called out of order (1)");
    }
 
    if ( conditional->type != CT_ON_PROC ) {
        CRITICAL_INTERNAL_ERROR("on_proc_index called out of order (1)");
    }
 
    if ( !procedure_exists( _environment, _label ) ) {
        CRITICAL_ON_CALL_WITH_NOT_EXISTENT_PROCEDURE(_label);
    }
 
    Variable * index = variable_resident( _environment, VT_BYTE, "(index)");
    
    variable_store( _environment, index->name, conditional->index );
 
    Variable * expression = variable_retrieve( _environment, conditional->expression->name );
 
    char newLabel[MAX_TEMPORARY_STORAGE]; sprintf(newLabel, "%s%d", conditional->label, (conditional->index+1) );
 
    cpu_bveq( _environment, variable_compare( _environment, expression->name, index->name )->realName, newLabel );
 
    call_procedure( _environment, _label );
 
    char newLabel2[MAX_TEMPORARY_STORAGE]; sprintf(newLabel2, "%sfinal", conditional->label );
 
    cpu_jump( _environment, newLabel2 );
 
    cpu_label( _environment, newLabel );
 
    ++conditional->index;
 
};

void on_proc_end( Environment * _environment ) {
 
    Conditional * conditional = _environment->conditionals;
 
    if ( ! conditional ) {
        CRITICAL_INTERNAL_ERROR("on_proc_end called out of order (1)");
    }
 
    if ( conditional->type != CT_ON_PROC ) {
        CRITICAL_INTERNAL_ERROR("on_proc_end called out of order (1)");
    }
 
    char newLabel2[MAX_TEMPORARY_STORAGE]; sprintf(newLabel2, "%sfinal", conditional->label );
 
    cpu_label( _environment, newLabel2 );
 
    _environment->conditionals->expression->locked = 0;
 
    _environment->conditionals = _environment->conditionals->next;
 
};