69 lines
2.1 KiB
Java
69 lines
2.1 KiB
Java
package io.github.applecommander.bastools.api.optimizations;
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import java.util.HashMap;
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import java.util.Map;
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import io.github.applecommander.bastools.api.Visitor;
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import io.github.applecommander.bastools.api.Visitors;
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import io.github.applecommander.bastools.api.model.Line;
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import io.github.applecommander.bastools.api.model.Program;
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import io.github.applecommander.bastools.api.model.Statement;
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import io.github.applecommander.bastools.api.model.Token;
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/**
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* Common base class for optimization visitors that allow the program tree to be rewritten.
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* Note that {@code #reassignments} is used to track line number movement and is <em>automatically</em>
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* applied at the end of the program visit.
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*/
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public class BaseVisitor implements Visitor {
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protected Map<Integer,Integer> reassignments = new HashMap<>();
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protected Program newProgram;
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@Override
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public Program visit(Program program) {
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newProgram = new Program();
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program.lines.forEach(l -> {
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Line line = l.accept(this);
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boolean lineKept = line != null && !line.statements.isEmpty();
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if (lineKept) {
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newProgram.lines.add(line);
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reassignments.replaceAll((k,v) -> v == null ? l.lineNumber : v);
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} else {
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// Make a place-holder for the reassignment; we'll patch it in once we find a line that sticks around.
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reassignments.put(l.lineNumber, null);
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}
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});
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if (!reassignments.isEmpty()) {
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// Now, renumber based on our findings!
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return newProgram.accept(Visitors.reassignVisitor(reassignments));
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} else {
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return newProgram;
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}
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}
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@Override
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public Line visit(Line line) {
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Line newLine = new Line(line.lineNumber, this.newProgram);
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line.statements.forEach(s -> {
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Statement statement = s.accept(this);
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if (statement != null) newLine.statements.add(statement);
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});
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return newLine;
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}
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@Override
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public Statement visit(Statement statement) {
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Statement newStatement = new Statement();
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statement.tokens.forEach(t -> {
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Token token = t.accept(this);
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if (token != null) newStatement.tokens.add(token);
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});
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return newStatement;
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}
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@Override
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public Token visit(Token token) {
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return token;
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}
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}
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