95 lines
1.6 KiB
C
95 lines
1.6 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "util.h"
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#include "symtable.h"
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object apply(object function, object parameters);
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object eval(object input)
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{
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object result;
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if (TYPE(input) == nilObject || TYPE(input) == numberObject ||
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TYPE(input) == errorObject)
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{
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result = input;
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}
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else if (TYPE(input) == symbolObject)
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{
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if (symbolExists(SYM(input)))
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{
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result = input;
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}
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else
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{
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deleteObject(input);
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TYPE(result) = errorObject;
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ERR(result) = unrecognizedSymbolError;
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}
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}
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else if (TYPE(input) == consObject)
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{
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if (!properList(input))
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{
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deleteObject(input);
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TYPE(result) = errorObject;
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ERR(result) = improperListError;
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}
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object *currentCell = &input;
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int noErrors = 1;
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while (TYPE(*currentCell) != nilObject)
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{
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CAR(*currentCell) = eval(CAR(*currentCell));
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if (TYPE(CAR(*currentCell)) == errorObject)
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{
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noErrors = 0;
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TYPE(result) = errorObject;
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ERR(result) = ERR(CAR(*currentCell));
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break;
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}
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currentCell = &CDR(*currentCell);
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}
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if (noErrors)
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{
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result = apply(CAR(input), CDR(input));
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}
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deleteObject(input);
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}
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return result;
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}
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object apply(object function, object parameters)
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{
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object result;
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if (TYPE(function) != symbolObject)
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{
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deleteObject(function);
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TYPE(result) = errorObject;
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ERR(result) = notApplicableError;
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}
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else if (symbolExists(SYM(function)))
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{
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object(*f)();
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if ((f = internalFunction(SYM(function))) != NULL)
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{
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result = f(parameters);
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}
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}
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else
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{
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deleteObject(function);
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TYPE(result) = errorObject;
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ERR(result) = unrecognizedSymbolError;
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}
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return result;
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}
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