diff options
Diffstat (limited to 'chapter01/src/main/java')
| -rw-r--r-- | chapter01/src/main/java/com/seaofnodes/simple/parser/Ast.java | 127 | ||||
| -rw-r--r-- | chapter01/src/main/java/com/seaofnodes/simple/parser/Parser.java | 75 |
2 files changed, 139 insertions, 63 deletions
diff --git a/chapter01/src/main/java/com/seaofnodes/simple/parser/Ast.java b/chapter01/src/main/java/com/seaofnodes/simple/parser/Ast.java index a93b230f..b11d1ddb 100644 --- a/chapter01/src/main/java/com/seaofnodes/simple/parser/Ast.java +++ b/chapter01/src/main/java/com/seaofnodes/simple/parser/Ast.java @@ -1,48 +1,94 @@ +/* + * DO NOT REMOVE COPYRIGHT NOTICES OR THIS HEADER. + * <p> + * Contributor(s): + * <p> + * The Initial Developer of the Original Software is Dibyendu Majumdar. + * <p> + * This file is part of the Sea Of Nodes Simple Programming language + * implementation. See https://github.com/SeaOfNodes/Simple + * <p> + * The contents of this file are subject to the terms of the + * Apache License Version 2 (the "APL"). You may not use this + * file except in compliance with the License. A copy of the + * APL may be obtained from: + * http://www.apache.org/licenses/LICENSE-2.0 + */ package com.seaofnodes.simple.parser; -import com.seaofnodes.simple.common.CompilerException; import com.seaofnodes.simple.lexer.ecstasy.Token; import java.util.ArrayList; import java.util.List; +import java.util.stream.Collectors; -public abstract class Ast { +/** + * A simple AST definition. + */ +public class Ast { - public static class Node { + private Ast() { } - public static class Expr extends Node { + public interface Node { + } + + public abstract static class Expr implements Node { public final Token op; - public Expr(Token op) { + protected Expr(Token op) { this.op = op; } } + /** + * A name in the language + */ public static class Identifier extends Expr { public final String name; + public Identifier(Token op) { super(op); name = op.getValueText(); } + + @Override + public String toString() { + return name; + } } + /** + * Reference to a name in the language + */ public static class Symbol extends Expr { public final String name; + public Symbol(Token op) { super(op); name = op.getValueText(); } + + @Override + public String toString() { + return name; + } } public static class Binary extends Expr { - public final Expr expr1, expr2; + public final Expr expr1; + public final Expr expr2; public Binary(Token op, Expr expr1, Expr expr2) { super(op); this.expr1 = expr1; this.expr2 = expr2; } + + @Override + public String toString() { + return "(" + expr1 + op.getValueText() + expr2 + ")"; + } } public static class Unary extends Expr { @@ -52,49 +98,65 @@ public abstract class Ast { super(op); this.expr = expr; } + + @Override + public String toString() { + return "(" + op.getValueText() + "(" + expr + "))"; + } } public static class Constant extends Expr { public Constant(Token op) { super(op); } + + @Override + public String toString() { + return op.getValueText(); + } } - public static class Statement extends Node { + public abstract static class Statement implements Node { } public static class IfElse extends Statement { public final Expr expr; - public final Statement ifStmt, elseStmt; + public final Statement ifStmt; + public final Statement elseStmt; public IfElse(Expr expr, Statement ifStmt, Statement elseStmt) { this.expr = expr; this.ifStmt = ifStmt; this.elseStmt = elseStmt; } + + @Override + public String toString() { + if (elseStmt != null) + return "if(" + expr + ") " + ifStmt + " else " + elseStmt; + return "if(" + expr + ") " + ifStmt; + } } public static class While extends Statement { - public Expr expr; - public Statement stmt; + public final Expr expr; + public final Statement stmt; - public While() { - } - public void init(Expr expr, Statement stmt) { + public While(Expr expr, Statement stmt) { this.expr = expr; this.stmt = stmt; } + + @Override + public String toString() { + return "while(" + expr.toString() + ") " + stmt; + } } public static class Break extends Statement { - public final Statement stmt; - - public Break(Statement stmt) { - if (stmt == null) - { - throw new CompilerException("uneclosed break"); - } - this.stmt = stmt; + @Override + public String toString() { + return "break;"; } } @@ -106,14 +168,24 @@ public abstract class Ast { this.identifier = identifier; this.expr = expr; } + + @Override + public String toString() { + return identifier.toString() + "=" + expr.toString() + ";"; + } } - public static class Type extends Node { + public static class Type implements Node { public final Token.Id typeId; public Type(Token.Id typeId) { this.typeId = typeId; } + + @Override + public String toString() { + return typeId.TEXT; + } } public static class Declare extends Statement { @@ -124,9 +196,20 @@ public abstract class Ast { this.type = type; this.identifier = identifier; } + + @Override + public String toString() { + return type.toString() + " " + identifier.toString() + ";"; + } } public static class Block extends Statement { public final List<Statement> stmtList = new ArrayList<>(); + + @Override + public String toString() { + return "{" + + stmtList.stream().map(Object::toString).collect(Collectors.joining()) + "}"; + } } } diff --git a/chapter01/src/main/java/com/seaofnodes/simple/parser/Parser.java b/chapter01/src/main/java/com/seaofnodes/simple/parser/Parser.java index b36942d4..263d0b41 100644 --- a/chapter01/src/main/java/com/seaofnodes/simple/parser/Parser.java +++ b/chapter01/src/main/java/com/seaofnodes/simple/parser/Parser.java @@ -1,4 +1,4 @@ -/** +/* * DO NOT REMOVE COPYRIGHT NOTICES OR THIS HEADER. * * Contributor(s): @@ -16,28 +16,28 @@ */ package com.seaofnodes.simple.parser; -import com.seaofnodes.simple.common.CompilerException; +import com.seaofnodes.simple.lexer.ecstasy.CompilerException; import com.seaofnodes.simple.lexer.ecstasy.Lexer; import com.seaofnodes.simple.lexer.ecstasy.Token; -import com.seaofnodes.simple.common.Severity; +import com.seaofnodes.simple.lexer.ecstasy.Severity; public class Parser { final Lexer lexer; Token look; - Ast.Statement statementEnclosing; public Parser(Lexer lexer) { this.lexer = lexer; } - Token nextOrEof() { + private Token nextOrEof() { if (lexer.hasNext()) return lexer.next(); return new Token(look.getStartPosition(), look.getEndPosition(), Token.Id.EOF); } - void nextToken() { + private void nextToken() { look = nextOrEof(); + // skip comments while (look.isComment()) { look = nextOrEof(); } @@ -47,12 +47,12 @@ public class Parser { } } - void error(Token t, String errorMessage) { + private void error(Token t, String errorMessage) { lexer.log(Severity.ERROR, errorMessage, t.getStartPosition(), t.getEndPosition()); throw new CompilerException(errorMessage + ": " + t.toDebugString()); } - void match(Token.Id tag) { + private void match(Token.Id tag) { if (look.getId() == tag) { nextToken(); } else { @@ -65,43 +65,40 @@ public class Parser { return parseProgram(); } - Ast.Statement parseProgram() { + private Ast.Statement parseProgram() { var block = new Ast.Block(); parseDeclarations(block); parseStatements(block); return block; } - void parseDeclarations(Ast.Block block) { - while (look.getId() == Token.Id.VAR) { + private boolean isTypeName(Token tok) { + return switch (tok.getId()) { + case TYPE_INT, TYPE_CHAR, TYPE_FLOAT -> true; + default -> false; + }; + } + + private void parseDeclarations(Ast.Block block) { + while (isTypeName(look)) { + var type = new Ast.Type(look.getId()); nextToken(); var tok = look; match(Token.Id.IDENTIFIER); - match(Token.Id.COLON); - var type = parseType(); match(Token.Id.SEMICOLON); var identifier = new Ast.Identifier(tok); block.stmtList.add(new Ast.Declare(type, identifier)); } } - Ast.Type parseType() { - if (look.getId() == Token.Id.LIT_INTA) { - nextToken(); - return new Ast.Type(look.getId()); - } - error(look, "syntax error: unsupported type (at present only Int type is allowed)"); - return null; - } - - void parseStatements(Ast.Block block) { + private void parseStatements(Ast.Block block) { while (look.getId() != Token.Id.EOF && look.getId() != Token.Id.R_CURLY) { block.stmtList.add(parseStatement()); } } - Ast.Statement parseStatement() { + private Ast.Statement parseStatement() { Ast.Expr x; Ast.Statement s1; Ast.Statement s2; @@ -120,22 +117,17 @@ public class Parser { return new Ast.IfElse(x, s1, s2); } case WHILE -> { - var whilenode = new Ast.While(); - var savedStmt = statementEnclosing; - statementEnclosing = whilenode; match(Token.Id.WHILE); match(Token.Id.L_PAREN); x = parseBool(); match(Token.Id.R_PAREN); s1 = parseStatement(); - whilenode.init(x, s1); - statementEnclosing = savedStmt; - return whilenode; + return new Ast.While(x, s1); } case BREAK -> { match(Token.Id.BREAK); match(Token.Id.SEMICOLON); - return new Ast.Break(statementEnclosing); + return new Ast.Break(); } case L_CURLY -> { return parseBlock(); @@ -146,7 +138,7 @@ public class Parser { } } - Ast.Statement parseBlock() { + private Ast.Statement parseBlock() { match(Token.Id.L_CURLY); var block = new Ast.Block(); parseDeclarations(block); @@ -155,16 +147,17 @@ public class Parser { return block; } - Ast.Statement parseAssign() { + private Ast.Statement parseAssign() { + Token tok = look; match(Token.Id.IDENTIFIER); - Ast.Identifier identifier = new Ast.Identifier(look); + Ast.Identifier identifier = new Ast.Identifier(tok); match(Token.Id.ASN); var s = new Ast.Assign(identifier, parseBool()); match(Token.Id.SEMICOLON); return s; } - Ast.Expr parseBool() { + private Ast.Expr parseBool() { var x = parseAnd(); while (look.getId() == Token.Id.COND_OR) { var tok = look; @@ -174,7 +167,7 @@ public class Parser { return x; } - Ast.Expr parseAnd() { + private Ast.Expr parseAnd() { var x = parseRelational(); while (look.getId() == Token.Id.COND_AND) { var tok = look; @@ -184,7 +177,7 @@ public class Parser { return x; } - Ast.Expr parseRelational() { + private Ast.Expr parseRelational() { var x = parseAddition(); while (look.getId() == Token.Id.COMP_EQ || look.getId() == Token.Id.COMP_NEQ || @@ -199,7 +192,7 @@ public class Parser { return x; } - Ast.Expr parseAddition() { + private Ast.Expr parseAddition() { var x = parseMultiplication(); while (look.getId() == Token.Id.ADD || look.getId() == Token.Id.SUB) { @@ -210,7 +203,7 @@ public class Parser { return x; } - Ast.Expr parseMultiplication() { + private Ast.Expr parseMultiplication() { var x = parseUnary(); while (look.getId() == Token.Id.MUL || look.getId() == Token.Id.DIV) { @@ -221,7 +214,7 @@ public class Parser { return x; } - Ast.Expr parseUnary() { + private Ast.Expr parseUnary() { if (look.getId() == Token.Id.SUB || look.getId() == Token.Id.NOT) { var tok = look; @@ -232,7 +225,7 @@ public class Parser { } } - Ast.Expr parsePrimary() { + private Ast.Expr parsePrimary() { switch (look.getId()) { case L_PAREN -> { nextToken(); |