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package ast.nodes;
import ast.types.*;
import java.util.ArrayList;
import semanticanalysis.SemanticError;
import semanticanalysis.SymbolTable;
import codegen.Label;
/**
* Node for the `if` statement of the grammar.
*/
public class IfNode implements Node {
private final Node guard;
private final Node thenBranch;
private final Node elseBranch;
public IfNode(Node guard, Node thenBranch, Node elseBranch) {
this.guard = guard;
this.thenBranch = thenBranch;
this.elseBranch = elseBranch;
}
@Override
public ArrayList<SemanticError> checkSemantics(SymbolTable ST, int _nesting, FunctionType ft) {
ArrayList<SemanticError> errors = new ArrayList<>();
errors.addAll(guard.checkSemantics(ST, _nesting, ft));
errors.addAll(thenBranch.checkSemantics(ST, _nesting, ft));
if (elseBranch != null) {
errors.addAll(elseBranch.checkSemantics(ST, _nesting, ft));
}
return errors;
}
@Override
public Type typeCheck() {
if (guard.typeCheck() instanceof BoolType) {
Type thenexp = thenBranch.typeCheck();
Type elseexp = elseBranch.typeCheck();
if (thenexp.getClass().equals(elseexp.getClass())) {
return thenexp;
} else {
System.out.println("Type Error: incompatible types in then and else branches.");
return new ErrorType();
}
} else {
System.out.println("Type Error: non boolean condition in if.");
return new ErrorType();
}
}
@Override
public String codeGeneration() {
String thenLabel = Label.newBasic("then");
String endLabel = Label.newBasic("end");
String guardS = guard.codeGeneration();
String thenS = thenBranch.codeGeneration();
String elseS = "";
if (elseBranch != null) {
elseS = elseBranch.codeGeneration();
}
// We're assuming that the guard is boolean or an operation which puts a
// true (1) or false (0) into A0.
return guardS +
"storei T1 1\n" +
// Check if A0 = true
"beq A0 T1 " + thenLabel + "\n" +
elseS +
"b " + endLabel + "\n" +
thenLabel + ":\n" +
thenS +
endLabel + ":\n";
}
@Override
public String printAST(String prefix) {
String str = prefix + "If\n" + guard.printAST(prefix + " ") + thenBranch.printAST(prefix + " ");
if (elseBranch != null) {
str += elseBranch.printAST(prefix + " ");
}
return str;
}
@Override
public String toPrint(String prefix) {
String str = prefix + "if ";
str += guard.toPrint("") + ":\n";
str += thenBranch.toPrint(prefix + "\t") + "\n";
if (elseBranch != null) {
str += prefix + "else:\n";
str += elseBranch.toPrint(prefix + "\t") + "\n";
}
return str;
}
}
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