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package ast.nodes;
import ast.types.*;
import java.util.ArrayList;
import semanticanalysis.STentry;
import semanticanalysis.SemanticError;
import semanticanalysis.SymbolTable;
/**
* Node for the `assignment` statement of the grammar.
*/
public class AssignmentNode implements Node {
private final ExprListNode lhr;
private final Node assign;
private final ExprListNode rhr;
// Useful for code gen
private int offset;
private boolean alreadyDef;
public AssignmentNode(Node lhr, Node assign, Node rhr) {
this.lhr = (ExprListNode) lhr;
this.assign = assign;
this.rhr = (ExprListNode) rhr;
this.alreadyDef = false;
}
@Override
public ArrayList<SemanticError> checkSemantics(SymbolTable ST, int _nesting, FunctionType ft) {
ArrayList<SemanticError> errors = new ArrayList<>();
// DO NOT CHECK lhr
errors.addAll(assign.checkSemantics(ST, _nesting, ft));
errors.addAll(rhr.checkSemantics(ST, _nesting, ft));
int lsize = lhr.getSize();
for (int i = 0; i < lsize; i++) {
ExprNode leftAtom = (ExprNode) lhr.getElem(i);
STentry e = ST.lookup(leftAtom.getId());
if (ft != null) {
ft.addLocalVar();
}
if (e == null) {
ST.insert(leftAtom.getId(), new AtomType(), _nesting, "");
e = ST.lookup(leftAtom.getId());
} else {
int ns = e.getNesting();
if (_nesting == ns) {
this.alreadyDef = true;
}
}
offset = e.getOffset();
}
return errors;
}
// TODO: check it out for this type
@Override
public Type typeCheck() {
return rhr.typeCheck();
}
@Override
public String codeGeneration() {
String rhrString = rhr.codeGeneration();
String lhrString = "";
ExprNode leftAtom = (ExprNode) lhr.getElem(0);
// The code generation for the left atom returns a `store A0 0(T1)` at
// the end but we do not want that command.
// So, we'll have a string with the substring + the offset.
String leftAtomCode = leftAtom.codeGeneration();
lhrString += leftAtomCode.substring(0, leftAtomCode.length() - 17) + offset;
// If the variable name is previously defined it'll load the variable
// from the `0(T1)`, otherwise it'll push the `A0` register at the top
// of the stack.
if (!this.alreadyDef) {
lhrString += "\npushr A0\n";
} else {
lhrString += "\nload A0 0(T1)\n";
}
return rhrString + lhrString;
}
@Override
public String toPrint(String prefix) {
return prefix + "Assignment\n" + lhr.toPrint(prefix + " ") + assign.toPrint(prefix + " ")
+ rhr.toPrint(prefix + " ");
}
}
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