446 lines
15 KiB
Java
446 lines
15 KiB
Java
package io.gitlab.jfronny.muscript.compiler;
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import io.gitlab.jfronny.muscript.ast.*;
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import io.gitlab.jfronny.muscript.ast.bool.*;
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import io.gitlab.jfronny.muscript.ast.compare.*;
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import io.gitlab.jfronny.muscript.ast.conditional.UnresolvedConditional;
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import io.gitlab.jfronny.muscript.ast.dynamic.*;
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import io.gitlab.jfronny.muscript.ast.math.*;
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import io.gitlab.jfronny.muscript.ast.string.Concatenate;
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import io.gitlab.jfronny.muscript.data.Script;
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import io.gitlab.jfronny.muscript.error.*;
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import java.util.*;
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public class Parser {
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private final Lexer lexer;
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private final TokenData previous = new TokenData();
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private final TokenData current = new TokenData();
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public static Expr<?> parse(String source) {
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return new Parser(new Lexer(source)).parse().optimize();
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}
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public static Script parseScript(String source) {
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return new Parser(new Lexer(source)).parseScript().optimize();
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}
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public Parser(Lexer lexer) {
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this.lexer = lexer;
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}
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/**
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* Generate a single expression.
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* Must exhaust the source!
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*
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* @return the resulting expression
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*/
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public Expr<?> parse() {
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advance();
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Expr<?> expr = expression();
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if (!isAtEnd())
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throw new ParseException(LocationalError.create(lexer.source, lexer.start, lexer.current - 1, "Unexpected element after end of expression"));
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return expr;
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}
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/**
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* Generate a script instance.
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* Multiple instructions will be executed in sequence and the result of the last one will be returned.
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*
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* @return the resulting expression
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*/
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public Script parseScript() {
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advance();
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List<Expr<?>> expressions = new LinkedList<>();
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while (!isAtEnd()) {
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expressions.add(expression());
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match(Token.Semicolon); // Consume semicolon if present
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}
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if (expressions.isEmpty()) throw new ParseException(LocationalError.create(lexer.source, lexer.start, lexer.current - 1, "Missing any elements in closure"));
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return new Script(expressions);
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}
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// Expressions
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private Expr<?> expression() {
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try {
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return conditional();
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} catch (RuntimeException e) {
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if (e instanceof ParseException) throw e;
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else if (e instanceof LocationalException le) {
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throw new ParseException(le.asPrintable(lexer.source), le.getCause());
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} else throw error(e.getMessage());
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}
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}
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private Expr<?> conditional() {
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Expr<?> expr = and();
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if (match(Token.QuestionMark)) {
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int start = previous.start;
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int end = previous.current - 1;
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Expr<?> trueExpr = expression();
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consume(Token.Colon, "Expected ':' after first part of condition.");
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Expr<?> falseExpr = expression();
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expr = new UnresolvedConditional(start, end, asBool(expr), trueExpr, falseExpr);
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}
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return expr;
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}
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private Expr<?> and() {
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Expr<?> expr = or();
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while (match(Token.And)) {
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int start = previous.start;
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int end = previous.current - 1;
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Expr<?> right = or();
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expr = new And(start, end, asBool(expr), asBool(right));
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}
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return expr;
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}
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private Expr<?> or() {
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Expr<?> expr = equality();
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while (match(Token.Or)) {
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int start = previous.start;
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int end = previous.current - 1;
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Expr<?> right = equality();
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expr = new Or(start, end, asBool(expr), asBool(right));
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}
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return expr;
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}
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private Expr<?> equality() {
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Expr<?> expr = concat();
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while (match(Token.EqualEqual, Token.BangEqual)) {
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Token op = previous.token;
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int start = previous.start;
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int end = previous.current - 1;
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Expr<?> right = concat();
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BoolExpr e = new Equal(start, end, expr, right);
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if (op == Token.BangEqual) e = new Not(start, end, e);
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expr = e;
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}
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return expr;
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}
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private Expr<?> concat() {
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Expr<?> expr = comparison();
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while (match(Token.Concat)) {
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int start = previous.start;
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int end = previous.current - 1;
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Expr<?> right = comparison();
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expr = new Concatenate(start, end, asString(expr), asString(right));
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}
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return expr;
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}
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private Expr<?> comparison() {
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Expr<?> expr = term();
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while (match(Token.Greater, Token.GreaterEqual, Token.Less, Token.LessEqual)) {
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Token op = previous.token;
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int start = previous.start;
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int end = previous.current - 1;
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NumberExpr right = asNumber(term());
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expr = switch (op) {
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case Greater -> new Greater(start, end, asNumber(expr), right);
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case GreaterEqual -> new Not(start, end, new Less(start, end, asNumber(expr), right));
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case Less -> new Less(start, end, asNumber(expr), right);
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case LessEqual -> new Not(start, end, new Greater(start, end, asNumber(expr), right));
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default -> throw new IllegalStateException();
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};
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}
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return expr;
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}
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private Expr<?> term() {
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Expr<?> expr = factor();
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while (match(Token.Plus, Token.Minus)) {
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Token op = previous.token;
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int start = previous.start;
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int end = previous.current - 1;
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NumberExpr right = asNumber(factor());
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expr = switch (op) {
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case Plus -> new Plus(start, end, asNumber(expr), right);
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case Minus -> new Minus(start, end, asNumber(expr), right);
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default -> throw new IllegalStateException();
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};
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}
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return expr;
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}
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private Expr<?> factor() {
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Expr<?> expr = exp();
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while (match(Token.Star, Token.Slash, Token.Percentage)) {
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Token op = previous.token;
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int start = previous.start;
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int end = previous.current - 1;
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NumberExpr right = asNumber(exp());
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expr = switch (op) {
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case Star -> new Multiply(start, end, asNumber(expr), right);
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case Slash -> new Divide(start, end, asNumber(expr), right);
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case Percentage -> new Modulo(start, end, asNumber(expr), right);
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default -> throw new IllegalStateException();
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};
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}
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return expr;
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}
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private Expr<?> exp() {
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Expr<?> expr = unary();
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while (match(Token.UpArrow)) {
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int start = previous.start;
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int end = previous.current - 1;
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NumberExpr right = asNumber(unary());
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expr = new Power(start, end, asNumber(expr), right);
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}
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return expr;
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}
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private Expr<?> unary() {
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if (match(Token.Bang, Token.Minus)) {
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Token op = previous.token;
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int start = previous.start;
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int end = previous.current - 1;
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Expr<?> right = unary();
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return switch (op) {
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case Bang -> new Not(start, end, asBool(right));
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case Minus -> new Invert(start, end, asNumber(right));
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default -> throw new IllegalStateException();
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};
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}
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return call();
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}
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private Expr<?> call() {
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Expr<?> expr = primary();
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while (match(Token.LeftParen, Token.Dot, Token.LeftBracket, Token.DoubleColon)) {
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int start = previous.start;
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int end = previous.current - 1;
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expr = switch (previous.token) {
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case LeftParen -> finishCall(start, end, expr);
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case Dot -> {
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TokenData name = consume(Token.Identifier, "Expected field name after '.'.");
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yield new Get(start, end, asDynamic(expr), Expr.literal(name.start, name.current - 1, name.lexeme));
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}
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case DoubleColon -> {
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DynamicExpr callable;
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if (match(Token.Identifier)) {
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callable = new Variable(previous.start, previous.current - 1, previous.lexeme);
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} else if (match(Token.LeftParen)) {
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callable = expression().asDynamicExpr();
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consume(Token.RightParen, "Expected ')' after expression.");
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} else throw error("Bind operator requires right side to be a literal identifier or to be wrapped in parentheses.");
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yield new Bind(start, end, callable, expr.asDynamicExpr());
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}
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case LeftBracket -> {
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expr = new Get(start, end, asDynamic(expr), expression());
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consume(Token.RightBracket, "Expected closing bracket");
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yield expr;
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}
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default -> throw new IllegalStateException();
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};
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}
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return expr;
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}
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private Expr<?> finishCall(int start, int end, Expr<?> callee) {
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List<Call.Arg> args = new ArrayList<>(2);
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if (!check(Token.RightParen)) {
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do {
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args.add(new Call.Arg(asDynamic(expression()), match(Token.Ellipsis)));
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} while (match(Token.Comma));
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}
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consume(Token.RightParen, "Expected ')' after function arguments.");
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return new Call(start, end, asDynamic(callee), args);
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}
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private Expr<?> primary() {
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if (match(Token.Null)) return Expr.literalNull(previous.start, previous.current - 1);
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if (match(Token.String)) return Expr.literal(previous.start, previous.current - 1, previous.lexeme);
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if (match(Token.True, Token.False)) return Expr.literal(previous.start, previous.current - 1, previous.lexeme.equals("true"));
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if (match(Token.Number)) return Expr.literal(previous.start, previous.current - 1, Double.parseDouble(previous.lexeme));
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if (match(Token.Identifier)) {
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int start = previous.start;
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int end = previous.current - 1;
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String name = previous.lexeme;
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if (match(Token.Assign)) return new Assign(start, end, name, expression().asDynamicExpr());
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else return new Variable(start, end, name);
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}
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if (match(Token.LeftParen)) {
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Expr<?> expr = expression();
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consume(Token.RightParen, "Expected ')' after expression.");
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return expr;
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}
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if (match(Token.LeftBrace)) {
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int start = previous.start;
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List<String> boundArgs = new LinkedList<>();
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boolean variadic = false;
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boolean first = true;
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while (!match(Token.Arrow)) {
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if (!first) consume(Token.Comma, "Closure parameters MUST be comma-seperated");
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first = false;
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consume(Token.Identifier, "Closure arguments MUST be identifiers");
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boundArgs.add(previous.lexeme);
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if (match(Token.Ellipsis)) {
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variadic = true;
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consume(Token.Arrow, "Variadic argument MUST be the last argument");
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break;
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}
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}
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List<Expr<?>> expressions = new LinkedList<>();
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while (!match(Token.RightBrace)) {
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expressions.add(expression());
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match(Token.Semicolon); // Consume semicolon if present
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}
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int end = previous.start;
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return new Closure(start, end, boundArgs, expressions, variadic);
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}
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throw error("Expected expression.");
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}
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// Type conversion
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private BoolExpr asBool(Expr<?> expression) {
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try {
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return expression.asBoolExpr();
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} catch (TypeMismatchException e) {
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throw error(e.getMessage(), expression);
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}
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}
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private NumberExpr asNumber(Expr<?> expression) {
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try {
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return expression.asNumberExpr();
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} catch (TypeMismatchException e) {
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throw error(e.getMessage(), expression);
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}
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}
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private StringExpr asString(Expr<?> expression) {
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try {
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return expression.asStringExpr();
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} catch (TypeMismatchException e) {
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throw error(e.getMessage(), expression);
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}
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}
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private DynamicExpr asDynamic(Expr<?> expression) {
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try {
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return expression.asDynamicExpr();
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} catch (TypeMismatchException e) {
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throw error(e.getMessage(), expression);
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}
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}
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// Helpers
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private ParseException error(String message) {
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return new ParseException(LocationalError.create(lexer.source, current.current - 1, message));
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}
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private ParseException error(String message, Expr<?> expr) {
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return new ParseException(LocationalError.create(lexer.source, expr.chStart, expr.chEnd, message));
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}
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private TokenData consume(Token token, String message) {
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if (check(token)) return advance();
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throw error(message);
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}
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private boolean match(Token... tokens) {
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for (Token token : tokens) {
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if (check(token)) {
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advance();
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return true;
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}
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}
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return false;
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}
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private boolean check(Token token) {
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if (isAtEnd()) return false;
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return current.token == token;
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}
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private TokenData advance() {
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previous.set(current);
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lexer.next();
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current.set(lexer.token, lexer.lexeme, lexer.start, lexer.current, lexer.ch);
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if (current.token == Token.Error) {
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throw error(current.lexeme);
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}
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return previous;
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}
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private boolean isAtEnd() {
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return current.token == Token.EOF;
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}
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// Token data
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private static class TokenData {
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public Token token;
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public String lexeme;
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public int start, current;
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public char ch;
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public void set(Token token, String lexeme, int start, int current, char ch) {
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this.token = token;
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this.lexeme = lexeme;
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this.start = start;
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this.current = current;
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this.ch = ch;
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}
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public void set(TokenData data) {
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set(data.token, data.lexeme, data.start, data.current, data.ch);
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}
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@Override
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public String toString() {
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return String.format("%s '%s'", token, lexeme);
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}
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}
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// Parse Exception
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public static class ParseException extends RuntimeException {
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public final LocationalError error;
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public ParseException(LocationalError error) {
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super(error.toString());
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this.error = error;
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}
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public ParseException(LocationalError error, Throwable cause) {
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super(error.toString(), cause);
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this.error = error;
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}
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}
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}
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