79 lines
2.1 KiB
C++
79 lines
2.1 KiB
C++
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#ifndef __substitute_h__
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#define __substitute_h__
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#include "yacasbase.h"
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#include "lispobject.h"
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#include "lispenvironment.h"
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/** Behaviour for substituting sub-expressions.
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*/
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class SubstBehaviourBase : public YacasBase
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{
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public:
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virtual ~SubstBehaviourBase();
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virtual LispBoolean Matches(LispPtr& aResult, LispPtr& aElement) = 0;
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};
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/** main routine that can perform substituting of expressions
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*/
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void InternalSubstitute(LispPtr& aTarget, LispPtr& aSource,
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SubstBehaviourBase& aBehaviour);
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/** Substing one expression for another. The simplest form
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* of substitution
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*/
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class SubstBehaviour : public SubstBehaviourBase
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{
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public:
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SubstBehaviour(LispEnvironment& aEnvironment,LispPtr& aToMatch,
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LispPtr& aToReplaceWith);
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virtual LispBoolean Matches(LispPtr& aResult, LispPtr& aElement);
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private:
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LispEnvironment& iEnvironment;
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LispPtr& iToMatch;
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LispPtr& iToReplaceWith;
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};
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/** subst behaviour for changing the local variables to have unique
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* names.
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*/
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class LocalSymbolBehaviour : public SubstBehaviourBase
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{
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public:
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LocalSymbolBehaviour(LispEnvironment& aEnvironment,
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LispString ** aOriginalNames,
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LispString ** aNewNames, LispInt aNrNames);
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virtual LispBoolean Matches(LispPtr& aResult, LispPtr& aElement);
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private:
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LispEnvironment& iEnvironment;
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LispString ** iOriginalNames;
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LispString ** iNewNames;
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LispInt iNrNames;
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};
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/** subst behaviour for backquote mechanism as in LISP.
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* When typing `(...) all occurrences of @a will be
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* replaced with:
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* 1) a evaluated if a is an atom
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* 2) function call with function name replaced by evaluated
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* head of function if a is a function. For instance, if
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* a is f(x) and f is g, then f(x) gets replaced by g(x)
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*/
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class BackQuoteBehaviour : public SubstBehaviourBase
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{
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public:
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BackQuoteBehaviour(LispEnvironment& aEnvironment)
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: iEnvironment(aEnvironment) {};
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virtual LispBoolean Matches(LispPtr& aResult, LispPtr& aElement);
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LispEnvironment& iEnvironment;
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};
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#endif
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