topLevelInitializer and initializer can be arrays now

peggyjs · Dec 11, 2023 · 121273b · 121273b
1 parent 7e0475b
commit 121273b
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Showing 13 changed files with 1,035 additions and 410 deletions.
diff --git a/docs/js/benchmark-bundle.min.js b/docs/js/benchmark-bundle.min.js
diff --git a/docs/js/test-bundle.min.js b/docs/js/test-bundle.min.js
diff --git a/docs/vendor/peggy/peggy.min.js b/docs/vendor/peggy/peggy.min.js
diff --git a/lib/compiler/asts.js b/lib/compiler/asts.js
@@ -2,6 +2,27 @@
 
 const visitor = require("./visitor");
 
+/**
+ * Combine two things, each of which might be an array, into a single value,
+ * in the order [...a, ...b].
+ *
+ * @template T
+ * @param {T | T[] | undefined} a
+ * @param {T | T[] | undefined} b
+ * @returns {T | T[] | undefined}
+ */
+function combinePossibleArrays(a, b) {
+  if (a) {
+    if (!b) {
+      return a;
+    }
+    const aa = Array.isArray(a) ? a : [a];
+    const bb = Array.isArray(b) ? b : [b];
+    return aa.concat(bb);
+  }
+  return b;
+}
+
 // AST utilities.
 const asts = {
   findRule(ast, name) {
@@ -88,47 +109,18 @@ const asts = {
   },
 
   combine(asts) {
-    let combined = null;
-    for (const ast of asts) {
-      if (combined) {
-        // Note: Change topLevelInitializer and initializer to be an array in
-        // order to keep the location along with.
-        if (ast.topLevelInitializer) {
-          if (combined.topLevelInitializer) {
-            // Try this and see if it's better than the other way in practice.
-            const init
-              = ast.topLevelInitializer
-                + "\n"
-                + combined.topLevelInitializer;
-
-            // Move imports to the top
-            let imports = "";
-            let nonImports = "";
-            for (const line of init.split(/[\r\n]+/)) {
-              if (/^\s*import/.test(line)) {
-                imports += line;
-              } else {
-                nonImports += line;
-              }
-            }
-            combined.topLevelInitializer = imports + "\n" + nonImports;
-          } else {
-            combined.topLevelInitializer = ast.topLevelInitializer;
-          }
-        }
-        if (ast.initializer) {
-          if (combined.initializer) {
-            combined.initializer = ast.initializer + "\n" + combined.initializer;
-          } else {
-            combined.initializer = ast.initializer;
-          }
-        }
-        combined.rules = combined.rules.concat(ast.rules);
-      } else {
-        combined = ast;
-      }
-    }
-    return combined;
+    return asts.reduce((combined, ast) => {
+      combined.topLevelInitializer = combinePossibleArrays(
+        combined.topLevelInitializer,
+        ast.topLevelInitializer
+      );
+      combined.initializer = combinePossibleArrays(
+        combined.initializer,
+        ast.initializer
+      );
+      combined.rules = combined.rules.concat(ast.rules);
+      return combined;
+    });
   },
 };
 

diff --git a/lib/compiler/index.js b/lib/compiler/index.js
@@ -5,6 +5,7 @@ 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");
@@ -61,6 +62,7 @@ const compiler = {
       removeProxyRules,
       mergeCharacterClasses,
       inferenceMatchResult,
+      moveImports,
     ],
     generate: [
       generateBytecode,

diff --git a/lib/compiler/passes/generate-js.js b/lib/compiler/passes/generate-js.js
@@ -849,7 +849,13 @@ function generateJS(ast, options) {
     const parts = [];
 
     if (ast.topLevelInitializer) {
-      parts.push(ast2SourceNode(ast.topLevelInitializer));
+      if (Array.isArray(ast.topLevelInitializer)) {
+        for (const tli of ast.topLevelInitializer) {
+          parts.push(ast2SourceNode(tli));
+        }
+      } else {
+        parts.push(ast2SourceNode(ast.topLevelInitializer));
+      }
       parts.push("");
     }
 
@@ -1283,7 +1289,13 @@ function generateJS(ast, options) {
     });
 
     if (ast.initializer) {
-      parts.push(ast2SourceNode(ast.initializer));
+      if (Array.isArray(ast.initializer)) {
+        for (const init of ast.initializer) {
+          parts.push(ast2SourceNode(init));
+        }
+      } else {
+        parts.push(ast2SourceNode(ast.initializer));
+      }
       parts.push("");
     }
 

diff --git a/lib/compiler/passes/move-imports.js b/lib/compiler/passes/move-imports.js
@@ -0,0 +1,21 @@
+// @ts-check
+"use strict";
+
+/**
+ * @typedef {import("../../peg")} PEG
+ */
+
+/**
+ *
+ * @param {PEG.ast.Grammar} ast
+ */
+function moveImports(ast) {
+  if (Array.isArray(ast.topLevelInitializer)) {
+    ast.topLevelInitializer
+      = ast.topLevelInitializer.filter(tli => tli.imports).concat(
+        ast.topLevelInitializer.filter(tli => !tli.imports)
+      );
+  }
+}
+
+module.exports = moveImports;
diff --git a/lib/compiler/visitor.js b/lib/compiler/visitor.js
@@ -29,11 +29,23 @@ const visitor = {
     const DEFAULT_FUNCTIONS = {
       grammar(node, ...args) {
         if (node.topLevelInitializer) {
-          visit(node.topLevelInitializer, ...args);
+          if (Array.isArray(node.topLevelInitializer)) {
+            for (const tli of node.topLevelInitializer) {
+              visit(tli, ...args);
+            }
+          } else {
+            visit(node.topLevelInitializer, ...args);
+          }
         }
 
         if (node.initializer) {
-          visit(node.initializer, ...args);
+          if (Array.isArray(node.initializer)) {
+            for (const init of node.initializer) {
+              visit(init, ...args);
+            }
+          } else {
+            visit(node.initializer, ...args);
+          }
         }
 
         node.rules.forEach(rule => visit(rule, ...args));