diff options
| -rw-r--r-- | MLKDynamicContext.h | 5 | ||||
| -rw-r--r-- | MLKDynamicContext.m | 15 | ||||
| -rw-r--r-- | MLKEnvironment.h | 6 | ||||
| -rw-r--r-- | MLKEnvironment.m | 55 |
4 files changed, 75 insertions, 6 deletions
diff --git a/MLKDynamicContext.h b/MLKDynamicContext.h index 0bfac44..c6df58f 100644 --- a/MLKDynamicContext.h +++ b/MLKDynamicContext.h @@ -47,9 +47,14 @@ -(id) findRestart:(MLKSymbol *)symbol; -(id) findHandler:(MLKSymbol *)symbol; -(id) findCatchTag:(MLKSymbol *)symbol; + -(id) valueForBinding:(MLKSymbol *)symbol; -(void) setValue:(id)value forBinding:(MLKSymbol *)symbol; -(void) addValue:(id)value forBinding:(MLKSymbol *)symbol; +-(void) addBinding:(MLKSymbol *)symbol; + +-(BOOL) boundp:(MLKSymbol *)symbol; +-(void) makunbound:(MLKSymbol *)symbol; -(void) dealloc; @end diff --git a/MLKDynamicContext.m b/MLKDynamicContext.m index 9b61bb6..5b44db7 100644 --- a/MLKDynamicContext.m +++ b/MLKDynamicContext.m @@ -157,6 +157,21 @@ [[self environment] addValue:value forBinding:symbol]; } +-(void) addBinding:(MLKSymbol *)symbol +{ + [[self environment] addBinding:symbol]; +} + +-(BOOL) boundp:(MLKSymbol *)symbol +{ + return [[self environment] boundp:symbol]; +} + +-(void) makunbound:(MLKSymbol *)symbol +{ + [[self environment] makunbound:symbol]; +} + -(void) dealloc { RELEASE (_conditionHandlers); diff --git a/MLKEnvironment.h b/MLKEnvironment.h index 20cf7ce..b1f8feb 100644 --- a/MLKEnvironment.h +++ b/MLKEnvironment.h @@ -27,6 +27,8 @@ NSMutableDictionary *_bindings; } ++(void) initialize; + -(MLKEnvironment *) init; -(MLKEnvironment *) initWithParent:(MLKEnvironment *)parent; -(MLKEnvironment *) initWithBindings:(NSDictionary *)bindings; @@ -34,6 +36,7 @@ -(MLKEnvironment *) parent; +-(void) addBinding:(MLKSymbol *)symbol; -(void) addBindings:(NSDictionary *)bindings; -(void) addValue:(id)value forBinding:(MLKSymbol *)symbol; -(void) setValue:(id)value forBinding:(MLKSymbol *)symbol; @@ -45,5 +48,8 @@ -(void) setBinding:(MLKSymbol *)symbol to:(id)value inEnvironment:(MLKEnvironment *)env; -(id) valueForBinding:(MLKSymbol *)symbol inEnvironment:(MLKEnvironment *)env; +-(BOOL) boundp:(MLKSymbol *)symbol; +-(void) makunbound:(MLKSymbol *)symbol; + -(void) dealloc; @end diff --git a/MLKEnvironment.m b/MLKEnvironment.m index 8c26519..8488dd2 100644 --- a/MLKEnvironment.m +++ b/MLKEnvironment.m @@ -16,14 +16,23 @@ * along with this program. If not, see <http://www.gnu.org/licenses/>. */ -#import <Foundation/NSDictionary.h> #import <Foundation/NSArray.h> +#import <Foundation/NSDictionary.h> +#import <Foundation/NSNull.h> #import "MLKEnvironment.h" #import "MLKUndefinedVariableException.h" +static id UNBOUND; + + @implementation MLKEnvironment ++(void) initialize +{ + UNBOUND = [[NSObject alloc] init]; +} + -(MLKEnvironment *) init { return [self initWithParent:nil bindings:nil]; @@ -60,7 +69,7 @@ -(void) setBinding:(MLKSymbol *)symbol to:(id)value inEnvironment:(MLKEnvironment *)env { - if ([[_bindings allKeys] containsObject:symbol]) + if ([_bindings objectForKey:symbol]) [_bindings setObject:value forKey:symbol]; else if (_parent) @@ -78,8 +87,18 @@ -(id) valueForBinding:(MLKSymbol *)symbol inEnvironment:(MLKEnvironment *)env { - if ([[_bindings allKeys] containsObject:symbol]) - return [_bindings objectForKey:symbol]; + id value; + if ((value = [_bindings objectForKey:symbol])) + { + if (value == [NSNull null]) + return nil; + else if (value == UNBOUND) + [[[MLKUndefinedVariableException alloc] initWithEnvironment:env + variableName:symbol] + raise]; + else + return value; + } else if (_parent) return [_parent valueForBinding:symbol]; @@ -87,7 +106,7 @@ [[[MLKUndefinedVariableException alloc] initWithEnvironment:env variableName:symbol] raise]; - + return nil; // avoid a stupid compiler warning } @@ -101,9 +120,14 @@ [_bindings setObject:value forKey:symbol]; } +-(void) addBinding:(MLKSymbol *)symbol +{ + [_bindings setObject:UNBOUND forKey:symbol]; +} + -(MLKEnvironment *) environmentForBinding:(MLKSymbol *)symbol { - if ([[_bindings allKeys] containsObject:symbol]) + if ([_bindings objectForKey:symbol]) return self; else if (_parent) return [_parent environmentForBinding:symbol]; @@ -111,6 +135,25 @@ return nil; } +-(BOOL) boundp:(MLKSymbol *)symbol +{ + id value; + if ((value = [_bindings objectForKey:symbol])) + return (value != UNBOUND); + else if (_parent) + return [_parent boundp:symbol]; + else + return NO; +} + +-(void) makunbound:(MLKSymbol *)symbol +{ + if ([_bindings objectForKey:symbol]) + [_bindings setObject:UNBOUND forKey:symbol]; + else if (_parent) + return [_parent makunbound:symbol]; +} + -(void) dealloc { RELEASE (_bindings); |