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pegjs/spec/api/generated-parser-api.spec.js

131 lines
3.9 KiB
JavaScript

describe("generated parser API", function() {
describe("parse", function() {
it("parses input", function() {
var parser = PEG.buildParser('start = "a"');
expect(parser.parse("a")).toBe("a");
});
it("throws an exception on syntax error", function() {
var parser = PEG.buildParser('start = "a"');
expect(function() { parser.parse("b"); }).toThrow();
});
describe("start rule", function() {
var parser = PEG.buildParser([
'a = "x" { return "a"; }',
'b = "x" { return "b"; }',
'c = "x" { return "c"; }'
].join("\n"), { allowedStartRules: ["b", "c"] });
describe("when |startRule| is not set", function() {
it("starts parsing from the first allowed rule", function() {
expect(parser.parse("x")).toBe("b");
});
});
describe("when |startRule| is set to an allowed rule", function() {
it("starts parsing from specified rule", function() {
expect(parser.parse("x", { startRule: "b" })).toBe("b");
expect(parser.parse("x", { startRule: "c" })).toBe("c");
});
});
describe("when |startRule| is set to a disallowed start rule", function() {
it("throws an exception", function() {
expect(
function() { parser.parse("x", { startRule: "a" }); }
).toThrow();
});
});
});
describe("tracing", function() {
var parser = PEG.buildParser([
'start = a / b',
'a = "a"',
'b = "b"'
].join("\n"), { trace: true });
describe("default tracer", function() {
it("traces using console.log", function() {
spyOn(console, "log");
parser.parse("b");
expect(console.log).toHaveBeenCalledWith("1:1 rule.enter start");
expect(console.log).toHaveBeenCalledWith("1:1 rule.enter a");
expect(console.log).toHaveBeenCalledWith("1:1 rule.fail a");
expect(console.log).toHaveBeenCalledWith("1:1 rule.enter b");
expect(console.log).toHaveBeenCalledWith("1:2 rule.match b");
expect(console.log).toHaveBeenCalledWith("1:2 rule.match start");
});
});
describe("custom tracers", function() {
describe("trace", function() {
it("receives tracing events", function() {
var tracer = { trace: function() { } };
spyOn(tracer, "trace");
parser.parse("b", { tracer: tracer });
expect(tracer.trace).toHaveBeenCalledWith({
type: 'rule.enter',
rule: 'start',
offset: 0,
line: 1,
column: 1
});
expect(tracer.trace).toHaveBeenCalledWith({
type: 'rule.enter',
rule: 'a',
offset: 0,
line: 1,
column: 1
});
expect(tracer.trace).toHaveBeenCalledWith({
type: 'rule.fail',
rule: 'a',
offset: 0,
line: 1,
column: 1
});
expect(tracer.trace).toHaveBeenCalledWith({
type: 'rule.enter',
rule: 'b',
offset: 0,
line: 1,
column: 1
});
expect(tracer.trace).toHaveBeenCalledWith({
type: 'rule.match',
rule: 'b',
result: 'b',
offset: 1,
line: 1,
column: 2
});
expect(tracer.trace).toHaveBeenCalledWith({
type: 'rule.match',
rule: 'start',
result: 'b',
offset: 1,
line: 1,
column: 2
});
});
});
});
});
it("accepts custom options", function() {
var parser = PEG.buildParser('start = "a"');
parser.parse("a", { foo: 42 });
});
});
});