Parser: tests & fixes

nois-lang · Jun 8, 2023 · b461e35 · b461e35
1 parent ffb37fc
commit b461e35
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Showing 4 changed files with 88 additions and 11 deletions.
diff --git a/src/index.ts b/src/index.ts
@@ -1,5 +1,5 @@
 import { tokenize } from './lexer/lexer'
-import { readFileSync } from 'fs'
+import { existsSync, readFileSync } from 'fs'
 import { join, resolve } from 'path'
 import { compactNode, parseModule, Parser } from './parser/parser'
 import { prettySourceMessage, prettySyntaxError } from './error'
@@ -17,7 +17,12 @@ if (!path) {
     console.log(usage)
     process.exit()
 }
-const source = { str: readFileSync(resolve(path)).toString(), filename: path }
+const sourcePath = resolve(path)
+if (!existsSync(sourcePath)) {
+    console.error(`no such file \`${path}\``)
+    process.exit()
+}
+const source = { str: readFileSync(sourcePath).toString(), filename: path }
 
 const tokens = tokenize(source.str)
 const parser = new Parser(tokens)

diff --git a/src/parser/parser.spec.ts b/src/parser/parser.spec.ts
@@ -27,4 +27,75 @@ describe('parser', () => {
             }]
         })
     })
+
+    it('parse if-expr', () => {
+        const { tree, errors } = parse('if a { b } else { c }')
+        expect(errors.length).toEqual(0)
+        expect(tree).toEqual({
+            'module': [{
+                'statement': [{
+                    'expr': [{
+                        'sub-expr': [{
+                            'operand': [{
+                                'if-expr': [
+                                    { 'if-keyword': 'if' },
+                                    { 'expr': [{ 'sub-expr': [{ 'operand': [{ 'identifier': 'a' }] }] }] },
+                                    {
+                                        'block': [
+                                            { 'o-brace': '{' },
+                                            {
+                                                'statement': [{
+                                                    'expr': [{ 'sub-expr': [{ 'operand': [{ 'identifier': 'b' }] }] }]
+                                                }]
+                                            },
+                                            { 'c-brace': '}' }
+                                        ]
+                                    },
+                                    { 'else-keyword': 'else' },
+                                    {
+                                        'block': [
+                                            { 'o-brace': '{' },
+                                            {
+                                                'statement': [{
+                                                    'expr': [{ 'sub-expr': [{ 'operand': [{ 'identifier': 'c' }] }] }]
+                                                }]
+                                            },
+                                            { 'c-brace': '}' }
+                                        ]
+                                    }
+                                ]
+                            }]
+                        }]
+                    }]
+                }]
+            }]
+        })
+    })
+
+    it('parse var-def miss identifier', () => {
+        const { errors } = parse('let = 4')
+        expect(errors.length).toEqual(1)
+        expect(errors[0]).toEqual({
+            'expected': ['identifier'],
+            'got': {
+                'kind': 'equals',
+                'location': {
+                    'end': 4,
+                    'start': 4
+                },
+                'value': '='
+            }
+        })
+    })
+
+    it('parse if-expr mismatch paren', () => {
+        const { errors } = parse('if a { b) }')
+        expect(errors.length).toEqual(1)
+        expect(errors[0]).toEqual({
+            'expected': [],
+            'got': { 'kind': 'c-paren', 'location': { 'end': 8, 'start': 8 }, 'value': ')' },
+            'message': 'expected operand'
+        })
+    })
+
 })
diff --git a/src/parser/parser.ts b/src/parser/parser.ts
@@ -375,6 +375,8 @@ const parseSubExpr = (parser: Parser): void => {
  * operand ::= if-expr | lambda-expr | O-PAREN expr C-PAREN | STRING | CHAR | NUMBER | IDENTIFIER | type-expr
  */
 const parseOperand = (parser: Parser): void => {
+    const dynamicTokens: TokenKind[] = ['string', 'char', 'number', 'identifier']
+
     const mark = parser.open()
     if (parser.at('if-keyword')) {
         parseIfExpr(parser)
@@ -386,12 +388,12 @@ const parseOperand = (parser: Parser): void => {
         parser.expect('c-paren')
     } else if (parser.at('identifier') && parser.nth(1) === 'o-angle') {
         parseTypeExpr(parser)
+    } else if (parser.atAny(dynamicTokens)) {
+        parser.expectAny(dynamicTokens)
     } else {
-        const dynamicTokens: TokenKind[] = ['string', 'char', 'number', 'identifier']
-        if (parser.atAny(dynamicTokens)) {
-            parser.expectAny(dynamicTokens)
-        }
+        parser.advanceWithError('expected operand')
     }
+
     parser.close(mark, 'operand')
 }
 
@@ -501,9 +503,9 @@ const parsePrefixOp = (parser: Parser): void => {
 const parsePostfixOp = (parser: Parser): void => {
     if (parser.at('o-paren')) {
         parseCallOp(parser)
+    } else {
+        parser.advanceWithError('expected postfix operator')
     }
-
-    parser.advanceWithError('expected postfix operator')
 }
 
 /**
@@ -512,9 +514,9 @@ const parsePostfixOp = (parser: Parser): void => {
 const parseCallOp = (parser: Parser): void => {
     if (parser.at('o-paren')) {
         parseArgs(parser)
+    } else {
+        parser.advanceWithError('expected call operator')
     }
-
-    parser.advanceWithError('expected call operator')
 }
 
 /**

diff --git a/tsconfig.json b/tsconfig.json
@@ -13,7 +13,6 @@
     "sourceMap": true,
     "outDir": "./dist",
     "lib": [
-      "dom",
       "es5",
       "scripthost",
       "es2015.symbol.wellknown",