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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 "MLKUndefinedVariableException.h"
@implementation MLKEnvironment
-(MLKEnvironment *) init
{
return [self initWithParent:nil bindings:nil];
}
-(MLKEnvironment *) initWithParent:(MLKEnvironment *)parent bindings:(NSDictionary *)bindings
{
_bindings = [[NSMutableDictionary alloc] initWithCapacity:10];
ASSIGN (_parent, parent);
[self addBindings: bindings];
return self;
}
-(MLKEnvironment *) initWithParent:(MLKEnvironment *)parent
{
return [self initWithParent:parent bindings:nil];
}
-(MLKEnvironment *) initWithBindings:(NSDictionary *)bindings
{
return [self initWithParent:nil bindings:bindings];
}
-(void) setBinding:(MLKSymbol *)symbol to:(id)value
{
[self setBinding:symbol to:value inEnvironment:self];
}
-(void) setBinding:(MLKSymbol *)symbol to:(id)value inEnvironment:(MLKEnvironment *)env
{
if ([[_bindings allKeys] containsObject:symbol])
[_bindings setObject:value forKey:symbol];
else
if (_parent)
[_parent setBinding:symbol to:value inEnvironment:env];
else
[[[MLKUndefinedVariableException alloc] initWithEnvironment:env
variableName:symbol]
raise];
}
-(id) valueForBinding:(MLKSymbol *)symbol
{
return [self valueForBinding:symbol];
}
-(id) valueForBinding:(MLKSymbol *)symbol inEnvironment:(MLKEnvironment *)env
{
if ([[_bindings allKeys] containsObject:symbol])
return [_bindings objectForKey:symbol];
else
if (_parent)
return [_parent valueForBinding:symbol];
else
[[[MLKUndefinedVariableException alloc] initWithEnvironment:env
variableName:symbol]
raise];;
return nil; // avoid a stupid compiler warning
}
-(void) addBindings:(NSDictionary *)bindings
{
[_bindings addEntriesFromDictionary:bindings];
}
-(void) addBinding:(MLKSymbol *)symbol to:(id)value
{
[_bindings setObject:value forKey:symbol];
}
@end
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