130 lines
2.9 KiB
Java
130 lines
2.9 KiB
Java
package table;
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import function.LispFunction;
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import sexpression.Cons;
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import sexpression.SExpression;
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import java.util.Stack;
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import static sexpression.Nil.NIL;
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public class ExecutionContext {
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private static ExecutionContext uniqueInstance = new ExecutionContext();
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public static ExecutionContext getInstance() {
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return uniqueInstance;
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}
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private SymbolTable scope;
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private Stack<LispFunctionRecurInfo> functionCalls;
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private boolean recur;
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private ExecutionContext() {
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clearContext();
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}
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public void clearContext() {
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this.scope = new SymbolTable();
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this.functionCalls = new Stack<>();
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this.clearRecur();
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}
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public SymbolTable getScope() {
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return scope;
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}
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public void setScope(SymbolTable scope) {
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this.scope = scope;
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}
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public void restoreGlobalScope() {
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while (!scope.isGlobal())
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scope = scope.getParent();
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}
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public SExpression lookupSymbolValue(String symbolName) {
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for (SymbolTable t = scope; t != null; t = t.getParent())
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if (t.contains(symbolName))
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return t.get(symbolName);
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return null;
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}
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public Cons toList() {
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Cons symbols = NIL;
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for (SymbolTable t = scope; t != null; t = t.getParent())
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symbols = new Cons(t.toList(), symbols);
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return symbols;
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}
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public void pushFunctionCall(LispFunction function) {
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functionCalls.push(new LispFunctionRecurInfo(function));
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}
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public void popFunctionCall() {
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functionCalls.pop();
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}
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public boolean isInFunctionCall() {
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return !functionCalls.empty();
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}
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public LispFunction getCurrentFunction() {
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return functionCalls.peek().getLispFunction();
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}
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public boolean isRecur() {
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return recur;
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}
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public void setRecur() {
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recur = true;
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}
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public void clearRecur() {
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recur = false;
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}
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public boolean isRecurInitializing() {
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return functionCalls.peek().isRecurInitializing();
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}
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public void setRecurInitializing() {
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functionCalls.peek().setRecurInitializing();
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}
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public void clearRecurInitializing() {
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functionCalls.peek().clearRecurInitializing();
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}
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public static class LispFunctionRecurInfo {
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private LispFunction lispFunction;
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private boolean recurInitializing;
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public LispFunctionRecurInfo(LispFunction lispFunction) {
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this.lispFunction = lispFunction;
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this.clearRecurInitializing();
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}
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public boolean isRecurInitializing() {
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return recurInitializing;
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}
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public void setRecurInitializing() {
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this.recurInitializing = true;
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}
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public void clearRecurInitializing() {
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this.recurInitializing = false;
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}
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public LispFunction getLispFunction() {
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return lispFunction;
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}
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}
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}
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