small tweak to the SlangNode class (#1396)

* avoid reassigning the same values when we know nothing changes

* reverting the early exit after having done some profiling

* instead of keeping leading and trailing offsets we just remember the outer bounds

Author: Janther

src/slang-nodes/ModifierDefinition.ts

@@ -10,7 +10,11 @@ import { FunctionBody } from './FunctionBody.js';
 
 import type * as ast from '@nomicfoundation/slang/ast';
 import type { AstPath, Doc, ParserOptions } from 'prettier';
-import type { CollectedMetadata, PrintFunction } from '../types.d.ts';
+import type {
+  AstLocation,
+  CollectedMetadata,
+  PrintFunction
+} from '../types.d.ts';
 import type { AstNode } from './types.d.ts';
 
 export class ModifierDefinition extends SlangNode {
@@ -45,14 +49,12 @@ export class ModifierDefinition extends SlangNode {
     this.updateMetadata(this.parameters, this.attributes, this.body);
 
     if (!this.parameters) {
-      const attributesLoc = this.attributes.loc;
-      const parametersOffset =
-        attributesLoc.start - attributesLoc.leadingOffset;
-      const parametersLoc = {
+      const parametersOffset = this.attributes.loc.outerStart;
+      const parametersLoc: AstLocation = {
+        outerStart: parametersOffset,
+        outerEnd: parametersOffset,
         start: parametersOffset,
-        end: parametersOffset,
-        leadingOffset: 0,
-        trailingOffset: 0
+        end: parametersOffset
       };
 
       this.parameters = Object.assign(

src/slang-nodes/SlangNode.ts

@@ -8,13 +8,14 @@ import { MultiLineNatSpecComment } from './MultiLineNatSpecComment.js';
 import { SingleLineComment } from './SingleLineComment.js';
 import { SingleLineNatSpecComment } from './SingleLineNatSpecComment.js';
 
+import type { NonterminalKind } from '@nomicfoundation/slang/cst';
 import type {
   AstLocation,
   CollectedMetadata,
   SlangAstNode
 } from '../types.d.ts';
 import type { Comment, StrictAstNode } from './types.d.ts';
-import type { TerminalNode } from './TerminalNode.js';
+import type { TerminalNode } from './TerminalNode.ts';
 
 function reversedIterator<T>(children: T[]): Iterable<T> {
   return {
@@ -30,7 +31,9 @@ function reversedIterator<T>(children: T[]): Iterable<T> {
   };
 }
 
-export class SlangNode {
+export abstract class SlangNode {
+  abstract readonly kind: TerminalKind | NonterminalKind;
+
   comments?: Comment[];
 
   loc: AstLocation;
@@ -41,12 +44,13 @@ export class SlangNode {
     enclosePeripheralComments = false
   ) {
     if (ast instanceof SlangTerminalNode) {
-      const offset = collected.offsets.get(ast.id) || 0;
+      const start = collected.offsets.get(ast.id) || 0;
+      const end = start + ast.textLength.utf16;
       this.loc = {
-        start: offset,
-        end: offset + ast.textLength.utf16,
-        leadingOffset: 0,
-        trailingOffset: 0
+        outerStart: start,
+        outerEnd: end,
+        start,
+        end
       };
       return;
     }
@@ -109,10 +113,10 @@ export class SlangNode {
     trailingOffset ??= triviaLength;
 
     this.loc = {
+      outerStart: initialOffset,
+      outerEnd: offset,
       start: initialOffset + leadingOffset,
-      end: offset - trailingOffset,
-      leadingOffset,
-      trailingOffset
+      end: offset - trailingOffset
     };
   }
 
@@ -121,26 +125,24 @@ export class SlangNode {
   ): void {
     const { loc } = this;
     // calculate correct loc object
-    if (loc.leadingOffset === 0) {
+    if (loc.outerStart === loc.start) {
       for (const childNode of childNodes) {
         if (childNode === undefined) continue;
-        const { leadingOffset, start } = childNode.loc;
+        const { outerStart, start } = childNode.loc;
 
-        if (start - leadingOffset === loc.start) {
-          loc.leadingOffset = leadingOffset;
+        if (outerStart === loc.start) {
           loc.start = start;
           break;
         }
       }
     }
 
-    if (loc.trailingOffset === 0) {
+    if (loc.outerEnd === loc.end) {
       for (const childNode of reversedIterator(childNodes)) {
         if (childNode === undefined) continue;
-        const { trailingOffset, end } = childNode.loc;
+        const { outerEnd, end } = childNode.loc;
 
-        if (end + trailingOffset === loc.end) {
-          loc.trailingOffset = trailingOffset;
+        if (outerEnd === loc.end) {
           loc.end = end;
           break;
         }

src/types.d.ts

@@ -20,8 +20,8 @@ interface Location {
 }
 
 interface AstLocation extends Location {
-  leadingOffset: number;
-  trailingOffset: number;
+  outerStart: number;
+  outerEnd: number;
 }
 
 type PrintFunction = (path: AstPath<AstNode>) => Doc;