Only parse JS code for imports if we are generating es-format JS.

.eslintrc.js

@@ -6,6 +6,7 @@ module.exports = {
   ignorePatterns: [
     "docs/",
     "lib/parser.js", // Generated
+    "lib/compiler/passes/js-imports.js", // Generated
     "examples/*.js", // Testing examples
     "test/vendor/",
     "test/cli/fixtures/bad.js", // Intentionally-invalid

lib/compiler/index.js

@@ -5,7 +5,6 @@ const generateJS = require("./passes/generate-js");
 const inferenceMatchResult = require("./passes/inference-match-result");
 const removeProxyRules = require("./passes/remove-proxy-rules");
 const mergeCharacterClasses = require("./passes/merge-character-classes");
-const moveImports = require("./passes/move-imports");
 const reportDuplicateLabels = require("./passes/report-duplicate-labels");
 const reportDuplicateRules = require("./passes/report-duplicate-rules");
 const reportInfiniteRecursion = require("./passes/report-infinite-recursion");
@@ -62,7 +61,6 @@ const compiler = {
       removeProxyRules,
       mergeCharacterClasses,
       inferenceMatchResult,
-      moveImports,
     ],
     generate: [
       generateBytecode,

lib/compiler/passes/generate-js.js

@@ -8,6 +8,7 @@ const VERSION = require("../../version");
 const { stringEscape, regexpClassEscape } = require("../utils");
 const { SourceNode } = require("source-map-generator");
 const GrammarLocation = require("../../grammar-location");
+const { parse: parseImport } = require("./js-imports.js");
 
 /**
  * @typedef {import("../../peg")} PEG
@@ -848,14 +849,30 @@ function generateJS(ast, options) {
   function generateToplevel() {
     const parts = [];
 
-    if (ast.topLevelInitializer) {
-      if (Array.isArray(ast.topLevelInitializer)) {
-        for (const tli of ast.topLevelInitializer) {
+    let topLevel = ast.topLevelInitializer;
+    if (topLevel) {
+      if (Array.isArray(topLevel)) {
+        if (options.format === "es") {
+          const imps = [];
+          const codes = [];
+          for (const tli of topLevel) {
+            const [imports, code] = parseImport(tli.code);
+            if (imports.code) {
+              imps.push(imports);
+              codes.push(code);
+            } else {
+              // Prefer the original
+              codes.push(tli);
+            }
+          }
+          topLevel = imps.concat(codes);
+        }
+        for (const tli of topLevel) {
           parts.push(ast2SourceNode(tli));
           parts.push("");
         }
       } else {
-        parts.push(ast2SourceNode(ast.topLevelInitializer));
+        parts.push(ast2SourceNode(topLevel));
         parts.push("");
       }
     }

package.json

@@ -23,7 +23,7 @@
   },
   "scripts": {
     "clean": "rimraf build browser bin/*.map && mkdir browser",
-    "parser": "node bin/peggy.js -o lib/parser.js --format commonjs src/parser.pegjs",
+    "parser": "node bin/peggy.js -o lib/parser.js --format commonjs src/parser.pegjs && node bin/peggy.js -o lib/compiler/passes/js-imports.js --format commonjs src/js-imports.peggy src/parser.pegjs",
     "examples": "node bin/peggy.js -c docs/js/options.js docs/js/examples.peggy",
     "set_version": "node ./tools/set_version",
     "lint": "eslint . --ext js,ts,mjs",

src/js-imports.peggy

@@ -0,0 +1,48 @@
+JSSource = imports:ImportDeclarations code:BareCodeBlock {
+  return [imports, {
+    type: "top_level_initializer",
+    code: code[0],
+    codeLocation: code[1],
+  }];
+}
+
+ImportDeclarations
+  = code:$ImportDeclaration* {
+    return {
+      type: "top_level_initializer",
+      code,
+      codeLocation: location()
+    };
+  }
+
+ImportDeclaration
+  = __ "import" __ ImportClause __ FromClause __ ";"?
+  / __ "import" __ ModuleSpecifier __ ";"?
+
+ImportClause
+  = ImportedDefaultBinding
+  / NameSpaceImport
+  / NamedImports
+  / ImportedDefaultBinding __ "," __ (NameSpaceImport / NamedImports)
+
+ImportedDefaultBinding = ImportedBinding
+NameSpaceImport = "*" __ "as" __ ImportedBinding
+NamedImports
+  = "{" __ "}"
+  / "{" __ ImportsList __ ","? __ "}"
+FromClause = "from" __ ModuleSpecifier
+ImportsList = ImportSpecifier|1.., __ "," __|
+ImportSpecifier
+  = ModuleExportName __ "as" __ ImportedBinding
+  / ImportedBinding
+ModuleSpecifier = StringLiteral
+ImportedBinding
+  = BindingIdentifier
+
+ModuleExportName
+  =  IdentifierName
+  / StringLiteral
+
+BindingIdentifier = id:IdentifierName &{
+  return reservedWords.indexOf(id[0]) === -1
+}

src/parser.pegjs

@@ -57,64 +57,14 @@ Grammar
     }
 
 TopLevelInitializer
-  = "{" "{" imports:ImportDeclarations code:BareCodeBlock "}" "}" EOS {
-    const ret = {
+  = "{" code:CodeBlock "}" EOS {
+      return {
         type: "top_level_initializer",
         code: code[0],
         codeLocation: code[1],
-        imports: false,
         location: location()
+      };
     }
-    if (imports[0]) {
-      return [
-        {
-          type: "top_level_initializer",
-          code: imports[0],
-          codeLocation: imports[1],
-          imports: true,
-          location: location()
-        },
-        ret
-      ];
-    }
-    return ret;
-  }
-
-ImportDeclarations
-  = imports:$ImportDeclaration* {
-    return [imports, location()]
-  }
-ImportDeclaration
-  = __ "import" __ ImportClause __ FromClause __ ";"?
-  / __ "import" __ ModuleSpecifier __ ";"?
-
-ImportClause
-  = ImportedDefaultBinding
-  / NameSpaceImport
-  / NamedImports
-  / ImportedDefaultBinding __ "," __ (NameSpaceImport / NamedImports)
-
-ImportedDefaultBinding = ImportedBinding
-NameSpaceImport = "*" __ "as" __ ImportedBinding
-NamedImports
-  = "{" __ "}"
-  / "{" __ ImportsList __ ","? __ "}"
-FromClause = "from" __ ModuleSpecifier
-ImportsList = ImportSpecifier|1.., __ "," __|
-ImportSpecifier
-  = ModuleExportName __ "as" __ ImportedBinding
-  / ImportedBinding
-ModuleSpecifier = StringLiteral
-ImportedBinding
-  = BindingIdentifier
-
-ModuleExportName
-  =  IdentifierName
-  / StringLiteral
-
-BindingIdentifier = id:IdentifierName &{
-  return reservedWords.indexOf(id[0]) === -1
-}
 
 Initializer
   = code:CodeBlock EOS {

test/cli/fixtures/useFrags/identifier.peggy

@@ -1 +1,5 @@
+{{
+  // Useless TLI with NO import
+  const G = "global";
+}}
 id = IdentifierName

test/cli/fixtures/useFrags/package.json

@@ -5,7 +5,7 @@
   "type": "module",
   "private": "true",
   "scripts": {
-    "build": "../../../../bin/peggy.js identifier.peggy npm:frags/unicode.peggy && ../../../../bin/peggy.js fs.peggy npm:frags/path.peggy"
+    "build": "../../../../bin/peggy.js --format es identifier.peggy npm:frags/unicode.peggy && ../../../../bin/peggy.js --format es fs.peggy npm:frags/path.peggy"
   },
   "author": "Joe Hildebrand <joe-github@cursive.net>",
   "license": "MIT",

test/cli/run.spec.ts

@@ -856,7 +856,7 @@ Options:
     let input1 = path.join(__dirname, "fixtures", "useFrags", "identifier.peggy");
     let out = path.join(__dirname, "fixtures", "useFrags", "identifier.js");
     await expect(exec({
-      args: [input1, "npm:frags/unicode.peggy"],
+      args: ["--format", "es", input1, "npm:frags/unicode.peggy"],
       exitCode: 0,
     })).resolves.toBe("");
 
@@ -865,15 +865,15 @@ Options:
     input1 = path.join(__dirname, "fixtures", "useFrags", "fs.peggy");
     out = path.join(__dirname, "fixtures", "useFrags", "fs.js");
     await expect(exec({
-      args: [input1, "npm:frags/path.peggy"],
+      args: ["--format", "es", input1, "npm:frags/path.peggy"],
       exitCode: 0,
     })).resolves.toBe("");
 
     fs.unlinkSync(out);
 
     out = path.join(__dirname, "..", "..", "path.js");
     await expect(exec({
-      args: ["npm:frags/path.peggy"],
+      args: ["--format", "es", "npm:frags/path.peggy"],
 
       exitCode: 0,
     })).resolves.toBe("");

test/unit/parser.spec.js

@@ -60,7 +60,7 @@ describe("Peggy grammar parser", () => {
   const ruleB               = { type: "rule",        name: "b",          expression: literalEfgh };
   const ruleC               = { type: "rule",        name: "c",          expression: literalIjkl };
   const ruleStart           = { type: "rule",        name: "start",      expression: literalAbcd };
-  const topLevelInitializer = { type: "top_level_initializer", code: " top level code ", imports: false };
+  const topLevelInitializer = { type: "top_level_initializer", code: " top level code " };
   const initializer         = { type: "initializer",           code: " code " };
 
   function oneRuleGrammar(expression) {
@@ -1136,7 +1136,6 @@ c = @'ijkl'
       topLevelInitializer: {
         type: "top_level_initializer",
         code: "\n  const foo = 12;\n",
-        imports: false,
         codeLocation: {
           source: undefined,
           start: { offset: 3, line: 2, column: 3 },