compile.c

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LIST *
compile_local(
    PARSE   *parse,
    FRAME *frame )
{
    LIST *l;
    SETTINGS *s = 0;
    LIST    *nt = parse_evaluate( parse->left, frame );
    LIST    *ns = parse_evaluate( parse->right, frame );
    LIST    *result;

    if( DEBUG_COMPILE )
    {
        debug_compile( 0, "local", frame);
        list_print( nt );
        printf( " = " );
        list_print( ns );
        printf( "\n" );
    }

    /* Initial value is ns */

    for( l = nt; l; l = list_next( l ) )
        s = addsettings( s, VAR_SET, l->string, list_copy( (LIST*)0, ns ) );

    list_free( ns );
    list_free( nt );

    /* Note that callees of the current context get this "local" */
    /* variable, making it not so much local as layered. */

    pushsettings( s );
    result = parse_evaluate( parse->third, frame );
    popsettings( s );

    freesettings( s );

    return result;
}

/*
 * compile_null() - do nothing -- a stub for parsing
 */

LIST *
compile_null(
    PARSE   *parse,
    FRAME *frame )
{
    return L0;
}

/*
 * compile_on() - run rule under influence of on-target variables
 *
 * 	parse->left	list of files to include (can only do 1)
 *	parse->right	rule to run
 *
 * EXPERIMENTAL!
 */

LIST *
compile_on(
	PARSE	*parse,
	FRAME	*frame )
{
	LIST    *nt = parse_evaluate( parse->left, frame );
	LIST	*result = 0;

	if( DEBUG_COMPILE )
	{
	    debug_compile( 0, "on", frame );
	    list_print( nt );
	    printf( "\n" );
	}

	if( nt )
	{
	    TARGET *t = bindtarget( nt->string );
	    pushsettings( t->settings );

	    result = parse_evaluate( parse->right, frame );

	    popsettings( t->settings );
	}

	list_free( nt );

	return result;
}


/*
 * compile_rule() - compile a single user defined rule
 *
 *  parse->string   name of user defined rule
 *  parse->left parameters (list of lists) to rule, recursing left
 *
 * Wrapped around evaluate_rule() so that headers() can share it.
 */

LIST *
compile_rule(
    PARSE   *parse,
    FRAME *frame )
{
    FRAME       inner[1];
    LIST    *result;
    PARSE   *p;
    

    /* Build up the list of arg lists */

    frame_init( inner );
    inner->prev = frame;
    inner->prev_user = frame->module->user_module ? frame : frame->prev_user;
    inner->module = frame->module; /* This gets fixed up in evaluate_rule(), below */
    inner->procedure = parse;

    for( p = parse->left; p; p = p->left )
        lol_add( inner->args, parse_evaluate( p->right, frame ) );

    /* And invoke rule */

    result = evaluate_rule( parse->string, inner );

    frame_free( inner );

    return result;
}

static void argument_error( char* message, RULE* rule, FRAME* frame, LIST* arg )
{
    LOL* actual = frame->args;
    assert( frame->procedure != 0 );
    backtrace_line( frame->prev );
    printf( "*** argument error\n* rule %s ( ", frame->rulename );
    lol_print( rule->arguments->data );
    printf( " )\n* called with: ( " );
    lol_print( actual );
    printf( " )\n* %s %s\n", message, arg ? arg->string : "" );
    print_source_line( rule->procedure );
    printf( "see definition of rule '%s' being called\n", rule->name );
    backtrace( frame->prev );
    exit(1);
}

/* define delimiters for type check elements in argument lists (and
 * return type specifications, eventually)
 */
# define TYPE_OPEN_DELIM '['
# define TYPE_CLOSE_DELIM ']'

/* is_type_name - true iff the given string represents a type check
 * specification
 */
static int
is_type_name( char* s )
{
    return s[0] == TYPE_OPEN_DELIM
        && s[strlen(s) - 1] == TYPE_CLOSE_DELIM;
}

/*
 * arg_modifier - if the next element of formal is a single character,
 * return that; return 0 otherwise.  Used to extract "*+?" modifiers
 * from argument lists.
 */
static char
arg_modifier( LIST* formal )
{
    if ( formal->next )
    {
        char *next = formal->next->string;
        if ( next && next[0] != 0 && next[1] == 0 )
            return next[0];
    }
    return 0;
}

/*
 * type_check - checks that each element of values satisfies the
 * requirements of type_name.
 *
 *      caller   - the frame of the rule calling the rule whose
 *                 arguments are being checked
 *
 *      called   - the rule being called
 *
 *      arg_name - a list element containing the name of the argument
 *                 being checked
 */
static void
type_check( char* type_name, LIST *values, FRAME* caller, RULE* called, LIST* arg_name )
{
    static module_t *typecheck = 0;

    /* if nothing to check, bail now */
    if ( !values || !type_name )
        return;

    if ( !typecheck )
        typecheck = bindmodule(".typecheck");

    /* if the checking rule can't be found, also bail */
    {
        RULE checker_, *checker = &checker_;

        checker->name = type_name;
        if ( !typecheck->rules || !hashcheck( typecheck->rules, (HASHDATA**)&checker ) )
            return;
    }
    
    exit_module( caller->module );
    
    while ( values != 0 )
    {
        LIST *error;
        FRAME frame[1];
        frame_init( frame );
        frame->module = typecheck;
        frame->prev = caller;
        frame->prev_user = caller->module->user_module ? caller : caller->prev_user;

        enter_module( typecheck );
        /* Prepare the argument list */
        lol_add( frame->args, list_new( L0, values->string ) );
        error = evaluate_rule( type_name, frame );
        
        exit_module( typecheck );
        
        if ( error )
            argument_error( error->string, called, caller, arg_name );

        frame_free( frame );
		values = values->next;
    }

    enter_module( caller->module );
}

/*
 * collect_arguments() - local argument checking and collection
 */
static SETTINGS *
collect_arguments( RULE* rule, FRAME* frame )
{
    SETTINGS *locals = 0;
    
    LOL* all_actual = frame->args;
    LOL *all_formal = rule->arguments ? rule->arguments->data : 0;
    if ( all_formal ) /* Nothing to set; nothing to check */
    {
        int max = all_formal->count > all_actual->count
            ? all_formal->count
            : all_actual->count;
        
        int n;
        for ( n = 0; n < max ; ++n )
        {
            LIST *actual = lol_get( all_actual, n );
            char *type_name = 0;
            
            LIST *formal;
            for ( formal = lol_get( all_formal, n ); formal; formal = formal->next )
            {
                char* name = formal->string;

                if ( is_type_name(name) )
                {
                    if ( type_name )
                        argument_error( "missing argument name before type name:", rule, frame, formal );
                    
                    if ( !formal->next )
                        argument_error( "missing argument name after type name:", rule, frame, formal );

                    type_name = formal->string;
                }
                else
                {
                    LIST* value = 0;
                    char modifier;
                    LIST* arg_name = formal; /* hold the argument name for type checking */
                    
                    /* Stop now if a variable number of arguments are specified */
                    if ( name[0] == '*' && name[1] == 0 )
                        return locals;

                    modifier = arg_modifier( formal );
                
                    if ( !actual && modifier != '?' && modifier != '*' )
                        argument_error( "missing argument", rule, frame, formal );

                    switch ( modifier )
                    {
                    case '+':
                    case '*':
                        value = list_copy( 0, actual );
                        actual = 0;
                        /* skip an extra element for the modifier */
                        formal = formal->next; 
                        break;
                    case '?':
                        /* skip an extra element for the modifier */
                        formal = formal->next; 
                        /* fall through */
                    default:
                        if ( actual ) /* in case actual is missing */
                        {
                            value = list_new( 0, actual->string );
                            actual = actual->next;
                        }
                    }
                
                    locals = addsettings( locals, VAR_SET, name, value );
                    type_check( type_name, value, frame, rule, arg_name );
                    type_name = 0;
                }
            }
            
            if ( actual )
            {
                argument_error( "extra argument", rule, frame, actual );
            }
        }
    }
    return locals;
}

static int python_instance_number = 0;

RULE *
enter_rule( char *rulename, module_t *target_module );

#ifdef HAVE_PYTHON
static LIST*
call_python_function(RULE* r, FRAME* frame)
{
    LIST* result = 0;
    PyObject* arguments = PyTuple_New(frame->args->count);
    int i ;
    PyObject* py_result;

    for(i = 0; i < frame->args->count; ++i)
    {
        PyObject* arg = PyList_New(0);
        LIST* l = lol_get( frame->args, i);

        for(; l; l = l->next)
        {
            PyObject* v = PyString_FromString(l->string);
            /* Steals reference to 'v' */
            PyList_Append(arg, v);            
        }
        /* Steals reference to 'arg' */
        PyTuple_SetItem(arguments, i, arg);
    }

    frame_before_python_call = frame;
    py_result = PyObject_CallObject(r->python_function, arguments);
    Py_DECREF(arguments);
    if (py_result != NULL) {
        
        if (PyList_Check(py_result)) {
            int size = PyList_Size(py_result);
            int i;
            for(i = 0; i < size; ++i)
            {
                PyObject* item = PyList_GetItem(py_result, i);
                if (PyString_Check(item))
                {
                    result = list_new(result, 
                                      newstr(PyString_AsString(item)));
                }
                else
                {
                    fprintf(stderr, "Non-string object returned by Python call\n");
                }
            }
        }
        else if (PyInstance_Check(py_result))
        {
            static char instance_name[1000];
            static char imported_method_name[1000];
            module_t* m;
            PyObject* method;
            PyObject* method_name = PyString_FromString("foo");
            RULE* r;

            fprintf(stderr, "Got instance!\n");

            snprintf(instance_name, 1000,
                     "pyinstance%d", python_instance_number);
            snprintf(imported_method_name, 1000,
                     "pyinstance%d.foo", python_instance_number);
            ++python_instance_number;
            
            m = bindmodule(instance_name);

            /* This is expected to get bound method. */
            method = PyObject_GetAttr(py_result, method_name);
            
            r = bindrule( imported_method_name, root_module() );

            r->python_function = method;

            result = list_new(0, newstr(instance_name));    

            Py_DECREF(method_name);
        }
        else if (py_result == Py_None)
        {
            result = L0;
        }
        else
        {
            fprintf(stderr, "Non-list object returned by Python call\n");
        }

        Py_DECREF(py_result);
    }
    else {
        PyErr_Print();
        fprintf(stderr,"Call failed\n");
    }
    
    return result;
}

module_t* python_module()
{
    static module_t* python = 0;
    if ( !python )
        python = bindmodule("__python__");
    return python;
}

#endif

/*
 * evaluate_rule() - execute a rule invocation
 */

LIST *
evaluate_rule(
    char    *rulename,
    FRAME *frame )
{
    LIST      *result = L0;
    RULE          *rule;
    profile_frame prof[1];
    module_t    *prev_module = frame->module;
    
    LIST      *l;
    {
        LOL arg_context_, *arg_context = &arg_context_;
        if ( !frame->prev )
            lol_init(arg_context);
        else
            arg_context = frame->prev->args;
        
        l = var_expand( L0, rulename, rulename+strlen(rulename), arg_context, 0 );
    }

    if ( !l )
    {
        backtrace_line( frame->prev );
        printf( "warning: rulename %s expands to empty string\n", rulename );
        backtrace( frame->prev );
        return result;
    }

    rulename = l->string;