Test compiler interface in order to generate MatchResult. Fix type for Stages .d.ts to match reality. Simplify compiler.passes; it doesn't need to be an object that gets converted to an array; it can just be an array that gets copied

Author: hildjj

lib/compiler/index.js

@@ -39,22 +39,22 @@ const compiler = {
   // or modify it as needed. If the pass encounters a semantic error, it throws
   // |peg.GrammarError|.
   passes: {
-    check: {
+    check: [
       reportUndefinedRules,
       reportDuplicateRules,
       reportDuplicateLabels,
       reportInfiniteRecursion,
       reportInfiniteRepetition,
       reportIncorrectPlucking
-    },
-    transform: {
+    ],
+    transform: [
       removeProxyRules,
       inferenceMatchResult,
-    },
-    generate: {
+    ],
+    generate: [
       generateBytecode,
       generateJS
-    }
+    ]
   },
 
   // Generates a parser from a specified grammar AST. Throws |peg.GrammarError|

lib/compiler/passes/inference-match-result.js

@@ -59,6 +59,9 @@ function inferenceMatchResult(ast) {
           // 6 == 3! -- permutations count for all transitions from one match
           // state to another.
           // After 6 iterations the cycle with guarantee begins
+          // For example, an input of `start = [] start` will generate the
+          // sequence: 0 -> 1 -> 0 -> -1 -> 0 -> 1 (then cycle)
+
           // istanbul ignore next  This is canary test, shouldn't trigger in real life
           if (++count > 6) {
             throw new GrammarError(

lib/peg.d.ts

@@ -641,12 +641,6 @@ export namespace compiler {
     function build<F extends NodeTypes>(functions: F): Visitor<F>;
   }
 
-  /** Mapping from the pass name to the function that represents pass. */
-  interface Passes {
-    /** List of passes in the stage. Any concrete set of passes are not guaranteed. */
-    [key: string]: Pass;
-  }
-
   /**
    * Mapping from the stage name to the default pass suite.
    * Plugins can extend or replace the list of passes during configuration.
@@ -656,17 +650,17 @@ export namespace compiler {
      * Pack of passes that performing checks on the AST. This bunch of passes
      * executed in the very beginning of the compilation stage.
      */
-    check: Passes;
+    check: Pass[];
     /**
      * Pack of passes that performing transformation of the AST.
      * Various types of optimizations are performed here.
      */
-    transform: Passes;
+    transform: Pass[];
     /** Pack of passes that generates the code. */
-    generate: Passes;
+    generate: Pass[];
 
     /** Any additional stages that can be added in the future. */
-    [key: string]: Passes;
+    [key: string]: Pass[];
   }
 
   /** List of the compilation stages. */

lib/peg.js

@@ -91,12 +91,10 @@ const peg = {
   generate(grammar, options) {
     options = options !== undefined ? options : {};
 
-    function convertPasses(passes) {
+    function copyPasses(passes) {
       const converted = {};
-
       Object.keys(passes).forEach(stage => {
-        converted[stage] = Object.keys(passes[stage])
-          .map(name => passes[stage][name]);
+        converted[stage] = passes[stage].slice();
       });
 
       return converted;
@@ -105,7 +103,7 @@ const peg = {
     const plugins = "plugins" in options ? options.plugins : [];
     const config = {
       parser: peg.parser,
-      passes: convertPasses(peg.compiler.passes),
+      passes: copyPasses(peg.compiler.passes),
       reservedWords: peg.RESERVED_WORDS.slice(),
     };
 

test/types/peg.test-d.ts

@@ -308,6 +308,21 @@ describe("peg.d.ts", () => {
       "zero_or_more",
     ]);
   });
+
+  it("compiles", () => {
+    const ast = peggy.parser.parse("start = 'foo'", {
+      grammarSource: "it compiles",
+      reservedWords: peggy.RESERVED_WORDS.slice(),
+    });
+    expectType<peggy.ast.Grammar>(ast);
+    const parser = peggy.compiler.compile(
+      ast,
+      peggy.compiler.passes
+    );
+    expectType<peggy.Parser>(parser);
+    expectType<peggy.ast.MatchResult|undefined>(ast.rules[0].match);
+    expect(ast.rules[0].match).toBe(0);
+  });
 });
 
 describe("run tsd", () => {