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/* -*- mode: objc; coding: utf-8 -*- */
/* Copyright 2008, Matthias Benkard. */
#import <Foundation/NSDictionary.h>
#import <Foundation/NSArray.h>
#import "MLKEnvironment.h"
#import "MLKLinkedList.h"
#import "MLKCons.h"
#import "MLKUndefinedVariableException.h"
@implementation MLKEnvironment
-(MLKEnvironment *) init
{
_bindings = [[MLKLinkedList alloc] init];
return self;
}
-(MLKEnvironment *) initWithParent:(MLKEnvironment *)parent
{
ASSIGN (_bindings, parent->_bindings);
return self;
}
-(void) setBinding:(MLKSymbol *)symbol to:(id)value
{
MLKCons *cons;
for (cons = [_bindings firstCons]; cons; cons = [cons cdr])
{
NSMutableDictionary *dict = [cons car];
if ([[dict allKeys] containsObject:symbol])
{
[dict setObject:value forKey:symbol];
break;
}
}
[[[MLKUndefinedVariableException alloc] initWithEnvironment: self
variableName: symbol]
raise];
}
-(id) valueForBinding:(MLKSymbol *)symbol
{
MLKCons *cons;
for (cons = [_bindings firstCons]; cons; cons = [cons cdr])
{
NSMutableDictionary *dict = [cons car];
if ([[dict allKeys] containsObject:symbol])
{
return [dict objectForKey:symbol];
}
}
[[[MLKUndefinedVariableException alloc] initWithEnvironment: self
variableName: symbol]
raise];
return nil;
}
@end
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