add unit tests for Optional parser, rename String --> StringParser

lib/standard-clojure-style.js

@@ -372,7 +372,7 @@
   }
 
   // Terminal parser that matches a String
-  function String (opts) {
+  function StringParser (opts) {
     return {
       name: opts.name,
       parse: (txt, pos) => {
@@ -605,7 +605,7 @@
   parsers.discard = Seq({
     name: 'discard',
     parsers: [
-      String({ name: 'marker', str: '#_' }),
+      StringParser({ name: 'marker', str: '#_' }),
       Repeat({ parser: '_gap' }),
       Named({ name: '.body', parser: '_form' })
     ]
@@ -618,8 +618,8 @@
       Choice({
         parsers: [
           Char({ name: '.open', char: '{' }),
-          String({ name: '.open', str: '#{' }),
-          String({ name: '.open', str: '#::{' }),
+          StringParser({ name: '.open', str: '#{' }),
+          StringParser({ name: '.open', str: '#::{' }),
           Regex({ name: '.open', regex: /^#:{1,2}[a-zA-Z][a-zA-Z0-9.-_]*{/ })
         ]
       }),
@@ -3972,10 +3972,11 @@
     API._Char = Char
     API._Choice = Choice
     API._NotChar = NotChar
+    API._Optional = Optional
     API._Regex = Regex
     API._Repeat = Repeat
     API._Seq = Seq
-    API._String = String
+    API._StringParser = StringParser
 
     API._flattenTree = flattenTree
     API._parseJavaPackageWithClass = parseJavaPackageWithClass

test/internals.test.js

@@ -423,7 +423,7 @@ test('NotChar parser', () => {
 })
 
 test('String parser', () => {
-  const stringTest1 = scsLib._String({ str: 'foo', name: 'string_test_foo' })
+  const stringTest1 = scsLib._StringParser({ str: 'foo', name: 'string_test_foo' })
   expect(stringTest1.parse('foo', 0).name).toBe('string_test_foo')
   expect(stringTest1.parse('foo', 0).text).toBe('foo')
   expect(stringTest1.parse('foo', 0).startIdx).toBe(0)
@@ -478,16 +478,7 @@ test('Regex parser', () => {
 })
 
 test('Choice parser', () => {
-  const choiceTest1 = scsLib._Choice({
-    parsers: [
-      scsLib._Char({ char: 'a', name: '.a' }),
-      scsLib._Char({ char: 'b', name: '.b' }),
-      scsLib._Char({ char: 'c', name: '.c' })]
-  })
-  expect(choiceTest1.parse('a', 0).text).toBe('a')
-  expect(choiceTest1.parse('b', 0).text).toBe('b')
-  expect(choiceTest1.parse('c', 0).text).toBe('c')
-  expect(choiceTest1.parse('z', 0)).toBeNull()
+
 })
 
 test('Seq parser', () => {
@@ -622,6 +613,45 @@ test('Choice parser', () => {
   expect(choiceResult6.text).toBe('a')
 })
 
+test('Optional parser', () => {
+  const optTest1 = scsLib._Optional(scsLib._Char({ char: 'a', name: 'optional_a' }))
+
+  // Test successful match
+  const result1 = optTest1.parse('abc', 0)
+  expect(result1.startIdx).toBe(0)
+  expect(result1.endIdx).toBe(1)
+  expect(result1.name).toBe('optional_a')
+  expect(result1.text).toBe('a')
+
+  // Test no match - should return empty node at same position
+  const result2 = optTest1.parse('xyz', 0)
+  expect(result2.startIdx).toBe(0)
+  expect(result2.endIdx).toBe(0)
+  expect(result2.name).toBeUndefined()
+
+  // Test with offset
+  const result3 = optTest1.parse('xabc', 1)
+  expect(result3.startIdx).toBe(1)
+  expect(result3.endIdx).toBe(2)
+  expect(result3.name).toBe('optional_a')
+  expect(result3.text).toBe('a')
+
+  const optTest2 = scsLib._Optional(scsLib._StringParser({ str: 'foo', name: 'optional_foo' }))
+
+  // Test successful match
+  const result4 = optTest2.parse('foobar', 0)
+  expect(result4.startIdx).toBe(0)
+  expect(result4.endIdx).toBe(3)
+  expect(result4.name).toBe('optional_foo')
+  expect(result4.text).toBe('foo')
+
+  // Test no match
+  const result5 = optTest2.parse('bar', 0)
+  expect(result5.startIdx).toBe(0)
+  expect(result5.endIdx).toBe(0)
+  expect(result5.name).toBeUndefined()
+})
+
 test('parseJavaPackageWithClass', () => {
   const example1 = scsLib._parseJavaPackageWithClass('aaa.bbb.ccc.Ddd')
   expect(example1.package).toBe('aaa.bbb.ccc')