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/*
* Copyright (C) 2016 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
"use strict";
function parse(tokenizer)
{
let program;
let pushBackBuffer = [];
function nextToken()
{
if (pushBackBuffer.length)
return pushBackBuffer.pop();
let result = tokenizer.next();
if (result.done)
return {kind: "endOfFile", string: "<end of file>"};
return result.value;
}
function pushToken(token)
{
pushBackBuffer.push(token);
}
function peekToken()
{
let result = nextToken();
pushToken(result);
return result;
}
function consumeKind(kind)
{
let token = nextToken();
if (token.kind != kind) {
throw new Error("At " + token.sourceLineNumber + ": expected " + kind + " but got: " + token.string);
}
return token;
}
function consumeToken(string)
{
let token = nextToken();
if (token.string.toLowerCase() != string.toLowerCase())
throw new Error("At " + token.sourceLineNumber + ": expected " + string + " but got: " + token.string);
return token;
}
function parseVariable()
{
let name = consumeKind("identifier").string;
let result = {evaluate: Basic.Variable, name, parameters: []};
if (peekToken().string == "(") {
do {
nextToken();
result.parameters.push(parseNumericExpression());
} while (peekToken().string == ",");
consumeToken(")");
}
return result;
}
function parseNumericExpression()
{
function parsePrimary()
{
let token = nextToken();
switch (token.kind) {
case "identifier": {
let result = {evaluate: Basic.NumberApply, name: token.string, parameters: []};
if (peekToken().string == "(") {
do {
nextToken();
result.parameters.push(parseNumericExpression());
} while (peekToken().string == ",");
consumeToken(")");
}
return result;
}
case "number":
return {evaluate: Basic.Const, value: token.value};
case "operator":
switch (token.string) {
case "(": {
let result = parseNumericExpression();
consumeToken(")");
return result;
} }
break;
}
throw new Error("At " + token.sourceLineNumber + ": expected identifier, number, or (, but got: " + token.string);
}
function parseFactor()
{
let primary = parsePrimary();
let ok = true;
while (ok) {
switch (peekToken().string) {
case "^":
nextToken();
primary = {evaluate: Basic.NumberPow, left: primary, right: parsePrimary()};
break;
default:
ok = false;
break;
}
}
return primary;
}
function parseTerm()
{
let factor = parseFactor();
let ok = true;
while (ok) {
switch (peekToken().string) {
case "*":
nextToken();
factor = {evaluate: Basic.NumberMul, left: factor, right: parseFactor()};
break;
case "/":
nextToken();
factor = {evaluate: Basic.NumberDiv, left: factor, right: parseFactor()};
break;
default:
ok = false;
break;
}
}
return factor;
}
// Only the leading term in Basic can have a sign.
let negate = false;
switch (peekToken().string) {
case "+":
nextToken();
break;
case "-":
negate = true;
nextToken()
break;
}
let term = parseTerm();
if (negate)
term = {evaluate: Basic.NumberNeg, term: term};
let ok = true;
while (ok) {
switch (peekToken().string) {
case "+":
nextToken();
term = {evaluate: Basic.NumberAdd, left: term, right: parseTerm()};
break;
case "-":
nextToken();
term = {evaluate: Basic.NumberSub, left: term, right: parseTerm()};
break;
default:
ok = false;
break;
}
}
return term;
}
function parseConstant()
{
switch (peekToken().string) {
case "+":
nextToken();
return consumeKind("number").value;
case "-":
nextToken();
return -consumeKind("number").value;
default:
if (isStringExpression())
return consumeKind("string").value;
return consumeKind("number").value;
}
}
function parseStringExpression()
{
let token = nextToken();
switch (token.kind) {
case "string":
return {evaluate: Basic.Const, value: token.value};
case "identifier":
consumeToken("$");
return {evaluate: Basic.StringVar, name: token.string};
default:
throw new Error("At " + token.sourceLineNumber + ": expected string expression but got " + token.string);
}
}
function isStringExpression()
{
// A string expression must start with a string variable or a string constant.
let token = nextToken();
if (token.kind == "string") {
pushToken(token);
return true;
}
if (token.kind == "identifier") {
let result = peekToken().string == "$";
pushToken(token);
return result;
}
pushToken(token);
return false;
}
function parseRelationalExpression()
{
if (isStringExpression()) {
let left = parseStringExpression();
let operator = nextToken();
let evaluate;
switch (operator.string) {
case "=":
evaluate = Basic.Equals;
break;
case "<>":
evaluate = Basic.NotEquals;
break;
default:
throw new Error("At " + operator.sourceLineNumber + ": expected a string comparison operator but got: " + operator.string);
}
return {evaluate, left, right: parseStringExpression()};
}
let left = parseNumericExpression();
let operator = nextToken();
let evaluate;
switch (operator.string) {
case "=":
evaluate = Basic.Equals;
break;
case "<>":
evaluate = Basic.NotEquals;
break;
case "<":
evaluate = Basic.LessThan;
break;
case ">":
evaluate = Basic.GreaterThan;
break;
case "<=":
evaluate = Basic.LessEqual;
break;
case ">=":
evaluate = Basic.GreaterEqual;
break;
default:
throw new Error("At " + operator.sourceLineNumber + ": expected a numeric comparison operator but got: " + operator.string);
}
return {evaluate, left, right: parseNumericExpression()};
}
function parseNonNegativeInteger()
{
let token = nextToken();
if (!/^[0-9]+$/.test(token.string))
throw new Error("At ", token.sourceLineNumber + ": expected a line number but got: " + token.string);
return token.value;
}
function parseGoToStatement()
{
statement.kind = Basic.GoTo;
statement.target = parseNonNegativeInteger();
}
function parseGoSubStatement()
{
statement.kind = Basic.GoSub;
statement.target = parseNonNegativeInteger();
}
function parseStatement()
{
let statement = {};
statement.lineNumber = consumeKind("userLineNumber").userLineNumber;
program.statements.set(statement.lineNumber, statement);
let command = nextToken();
statement.sourceLineNumber = command.sourceLineNumber;
switch (command.kind) {
case "keyword":
switch (command.string.toLowerCase()) {
case "def":
statement.process = Basic.Def;
statement.name = consumeKind("identifier");
statement.parameters = [];
if (peekToken().string == "(") {
do {
nextToken();
statement.parameters.push(consumeKind("identifier"));
} while (peekToken().string == ",");
}
statement.expression = parseNumericExpression();
break;
case "let":
statement.process = Basic.Let;
statement.variable = parseVariable();
consumeToken("=");
if (statement.process == Basic.Let)
statement.expression = parseNumericExpression();
else
statement.expression = parseStringExpression();
break;
case "go": {
let next = nextToken();
if (next.string == "to")
parseGoToStatement();
else if (next.string == "sub")
parseGoSubStatement();
else
throw new Error("At " + next.sourceLineNumber + ": expected to or sub but got: " + next.string);
break;
}
case "goto":
parseGoToStatement();
break;
case "gosub":
parseGoSubStatement();
break;
case "if":
statement.process = Basic.If;
statement.condition = parseRelationalExpression();
consumeToken("then");
statement.target = parseNonNegativeInteger();
break;
case "return":
statement.process = Basic.Return;
break;
case "stop":
statement.process = Basic.Stop;
break;
case "on":
statement.process = Basic.On;
statement.expression = parseNumericExpression();
if (peekToken().string == "go") {
consumeToken("go");
consumeToken("to");
} else
consumeToken("goto");
statement.targets = [];
for (;;) {
statement.targets.push(parseNonNegativeInteger());
if (peekToken().string != ",")
break;
nextToken();
}
break;
case "for":
statement.process = Basic.For;
statement.variable = consumeKind("identifier").string;
consumeToken("=");
statement.initial = parseNumericExpression();
consumeToken("to");
statement.limit = parseNumericExpression();
if (peekToken().string == "step") {
nextToken();
statement.step = parseNumericExpression();
} else
statement.step = {evaluate: Basic.Const, value: 1};
consumeKind("newLine");
let lastStatement = parseStatements();
if (lastStatement.process != Basic.Next)
throw new Error("At " + lastStatement.sourceLineNumber + ": expected next statement");
if (lastStatement.variable != statement.variable)
throw new Error("At " + lastStatement.sourceLineNumber + ": expected next for " + statement.variable + " but got " + lastStatement.variable);
lastStatement.target = statement;
statement.target = lastStatement;
return statement;
case "next":
statement.process = Basic.Next;
statement.variable = consumeKind("identifier").string;
break;
case "print": {
statement.process = Basic.Print;
statement.items = [];
let ok = true;
while (ok) {
switch (peekToken().string) {
case ",":
nextToken();
statement.items.push({kind: "comma"});
break;
case ";":
nextToken();
break;
case "tab":
nextToken();
consumeToken("(");
statement.items.push({kind: "tab", value: parseNumericExpression()});
break;
case "\n":
ok = false;
break;
default:
if (isStringExpression()) {
statement.items.push({kind: "string", value: parseStringExpression()});
break;
}
statement.items.push({kind: "number", value: parseNumericExpression()});
break;
}
}
break;
}
case "input":
statement.process = Basic.Input;
statement.items = [];
for (;;) {
stament.items.push(parseVariable());
if (peekToken().string != ",")
break;
nextToken();
}
break;
case "read":
statement.process = Basic.Read;
statement.items = [];
for (;;) {
stament.items.push(parseVariable());
if (peekToken().string != ",")
break;
nextToken();
}
break;
case "restore":
statement.process = Basic.Restore;
break;
case "data":
for (;;) {
program.data.push(parseConstant());
if (peekToken().string != ",")
break;
nextToken();
}
break;
case "dim":
statement.process = Basic.Dim;
statement.items = [];
for (;;) {
let name = consumeKind("identifier").string;
consumeToken("(");
let bounds = [];
bounds.push(parseNonNegativeInteger());
if (peekToken().string == ",") {
nextToken();
bounds.push(parseNonNegativeInteger());
}
consumeToken(")");
statement.items.push({name, bounds});
if (peekToken().string != ",")
break;
consumeToken(",");
}
break;
case "option": {
consumeToken("base");
let base = parseNonNegativeInteger();
if (base != 0 && base != 1)
throw new Error("At " + command.sourceLineNumber + ": unexpected base: " + base);
program.base = base;
break;
}
case "randomize":
statement.process = Basic.Randomize;
break;
case "end":
statement.process = Basic.End;
break;
default:
throw new Error("At " + command.sourceLineNumber + ": unexpected command but got: " + command.string);
}
break;
case "remark":
// Just ignore it.
break;
default:
throw new Error("At " + command.sourceLineNumber + ": expected command but got: " + command.string + " (of kind " + command.kind + ")");
}
consumeKind("newLine");
return statement;
}
function parseStatements()
{
let statement;
do {
statement = parseStatement();
} while (!statement.process || !statement.process.isBlockEnd);
return statement;
}
return {
program()
{
program = {
process: Basic.Program,
statements: new Map(),
data: [],
base: 0
};
let lastStatement = parseStatements(program.statements);
if (lastStatement.process != Basic.End)
throw new Error("At " + lastStatement.sourceLineNumber + ": expected end");
return program;
},
statement(program_)
{
program = program_;
return parseStatement();
}
};
}