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-rw-r--r--MLKInterpreter.h7
-rw-r--r--MLKInterpreter.m82
-rw-r--r--MLKReadEvalPrintLoop.m30
3 files changed, 76 insertions, 43 deletions
diff --git a/MLKInterpreter.h b/MLKInterpreter.h
index 8fcc1ec..c149389 100644
--- a/MLKInterpreter.h
+++ b/MLKInterpreter.h
@@ -16,6 +16,7 @@
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
+#import <Foundation/NSArray.h>
#import <Foundation/NSObject.h>
@class MLKLexicalContext, MLKLexicalEnvironment;
@@ -24,7 +25,7 @@
@interface MLKInterpreter : NSObject
+(void) initialize;
-+(id) eval:(id)program
- inLexicalContext:(MLKLexicalContext *)context
- withEnvironment:(MLKLexicalEnvironment *)lexenv;
++(NSArray*) eval:(id)program
+ inLexicalContext:(MLKLexicalContext *)context
+ withEnvironment:(MLKLexicalEnvironment *)lexenv;
@end
diff --git a/MLKInterpreter.m b/MLKInterpreter.m
index 7fc14d7..0b50312 100644
--- a/MLKInterpreter.m
+++ b/MLKInterpreter.m
@@ -34,6 +34,23 @@
#import <Foundation/NSString.h>
+static id nullify (id value)
+{
+ if (value)
+ return value;
+ else
+ return [NSNull null];
+}
+
+static id denullify (id value)
+{
+ if (value == [NSNull null])
+ return nil;
+ else
+ return value;
+}
+
+
static MLKPackage *cl;
static MLKPackage *sys;
static MLKSymbol *IF;
@@ -80,9 +97,9 @@ static MLKSymbol *_LAMBDA;
}
-+(id) eval:(id)program
- inLexicalContext:(MLKLexicalContext *)context
- withEnvironment:(MLKLexicalEnvironment *)lexenv
++(NSArray*) eval:(id)program
+ inLexicalContext:(MLKLexicalContext *)context
+ withEnvironment:(MLKLexicalEnvironment *)lexenv
{
MLKDynamicContext *dynamicContext = [MLKDynamicContext currentContext];
@@ -102,18 +119,18 @@ static MLKSymbol *_LAMBDA;
else if ([context variableIsLexical:program])
{
//NSLog (@"Processing lexical variable.");
- return [lexenv valueForSymbol:program];
+ return [NSArray arrayWithObject:nullify([lexenv valueForSymbol:program])];
}
else
{
//NSLog (@"Processing special variable.");
- return [dynamicContext valueForSymbol:program];
+ return [NSArray arrayWithObject:nullify([dynamicContext valueForSymbol:program])];
}
}
else if (![program isKindOfClass:[MLKCons class]])
{
// Everything that is not a list or a symbol evaluates to itself.
- return program;
+ return [NSArray arrayWithObject:nullify(program)];
}
else
{
@@ -123,13 +140,15 @@ static MLKSymbol *_LAMBDA;
{
if (car == APPLY)
{
- MLKCons *rest = [self eval:[[[program cdr] cdr] car]
- inLexicalContext:context
- withEnvironment:lexenv];
+ MLKCons *rest = denullify([[self eval:[[[program cdr] cdr] car]
+ inLexicalContext:context
+ withEnvironment:lexenv]
+ objectAtIndex:0]);
- id <MLKFuncallable> function = [self eval:[[program cdr] car]
- inLexicalContext:context
- withEnvironment:lexenv];
+ id <MLKFuncallable> function = denullify([[self eval:[[program cdr] car]
+ inLexicalContext:context
+ withEnvironment:lexenv]
+ objectAtIndex:0]);
return [function applyToArray:(rest
? (id)[rest array]
@@ -144,19 +163,21 @@ static MLKSymbol *_LAMBDA;
id <MLKFuncallable> function;
- function = [self eval:[MLKCons cons:_LAMBDA with:lambdaListAndBody]
- inLexicalContext:context
- withEnvironment:lexenv];
+ function = denullify([[self eval:[MLKCons cons:_LAMBDA with:lambdaListAndBody]
+ inLexicalContext:context
+ withEnvironment:lexenv]
+ objectAtIndex:0]);
[context addMacro:function forSymbol:name];
- return name;
+ return [NSArray arrayWithObject:nullify(name)];
}
else if (car == EVAL)
{
- return [self eval:[self eval:[program cdr]
- inLexicalContext:context
- withEnvironment:lexenv]
+ return [self eval:denullify([[self eval:[program cdr]
+ inLexicalContext:context
+ withEnvironment:lexenv]
+ objectAtIndex:0])
inLexicalContext:[MLKLexicalContext globalContext]
withEnvironment:[MLKLexicalEnvironment
globalEnvironment]];
@@ -175,14 +196,14 @@ static MLKSymbol *_LAMBDA;
lambdaListName:lambdaList
context:context
environment:lexenv]);
- return closure;
+ return [NSArray arrayWithObject:nullify(closure)];
}
else if (car == LET)
{
id declarations;
id clauses;
id body;
- id result;
+ NSArray *result;
MLKLexicalContext *ctx;
MLKLexicalEnvironment *env;
MLKDynamicContext *dynctx;
@@ -240,9 +261,10 @@ static MLKSymbol *_LAMBDA;
else
{
variable = [clause car];
- value = [self eval:[[clause cdr] car]
- inLexicalContext:context
- withEnvironment:lexenv];
+ value = denullify([[self eval:[[clause cdr] car]
+ inLexicalContext:context
+ withEnvironment:lexenv]
+ objectAtIndex:0]);
}
if ([ctx variableIsLexical:variable])
@@ -293,7 +315,7 @@ static MLKSymbol *_LAMBDA;
}
else if (car == QUOTE)
{
- return [[program cdr] car];
+ return [NSArray arrayWithObject:nullify([[program cdr] car])];
}
else if (car == SETQ)
{
@@ -314,10 +336,11 @@ static MLKSymbol *_LAMBDA;
while (rest)
{
- id result = [self eval:[rest car]
- inLexicalContext:context
- withEnvironment:lexenv];
- [args addObject:(result ? (id)result : (id)[NSNull null])];
+ id result = [[self eval:[rest car]
+ inLexicalContext:context
+ withEnvironment:lexenv]
+ objectAtIndex:0];
+ [args addObject:result];
rest = [rest cdr];
}
@@ -338,6 +361,7 @@ static MLKSymbol *_LAMBDA;
[NSException raise:@"MLKNoSuchOperatorException"
format:@"%@ does not name a known operator.",
[car descriptionForLisp]];
+ return nil;
}
}
}
diff --git a/MLKReadEvalPrintLoop.m b/MLKReadEvalPrintLoop.m
index 4ccc339..e9e90db 100644
--- a/MLKReadEvalPrintLoop.m
+++ b/MLKReadEvalPrintLoop.m
@@ -27,6 +27,7 @@
#import <Foundation/NSAutoreleasePool.h>
#import <Foundation/NSException.h>
+#import <Foundation/NSNull.h>
#import <Foundation/NSString.h>
#import <editline/history.h>
@@ -87,7 +88,7 @@ static const char *prompt (EditLine *e) {
if (line_length > 1)
{
NSAutoreleasePool *pool;
- id result;
+ NSArray *results;
id code;
pool = [[NSAutoreleasePool alloc] init];
@@ -96,18 +97,25 @@ static const char *prompt (EditLine *e) {
NS_DURING
{
+ int i;
+
code = [MLKReader readFromString:[NSString stringWithUTF8String:line]];
- result = [MLKInterpreter eval:code
- inLexicalContext:[MLKLexicalContext
- globalContext]
- withEnvironment:[MLKLexicalEnvironment
- globalEnvironment]];
-
- if (result)
- printf ("%s\n", [[result descriptionForLisp] UTF8String]);
- else
- printf ("()\n");
+ results = [MLKInterpreter eval:code
+ inLexicalContext:[MLKLexicalContext
+ globalContext]
+ withEnvironment:[MLKLexicalEnvironment
+ globalEnvironment]];
+
+ for (i = 0; i < [results count]; i++)
+ {
+ id result = [results objectAtIndex:i];
+ if (result != [NSNull null])
+ printf ("%s\n", [[result descriptionForLisp] UTF8String]);
+ else
+ printf ("()\n");
+ }
+
}
NS_HANDLER
{
generated by cgit v1.2.3 (git 2.25.1) at 2024-05-19 12:52:54 +0000