review of printing patterns (#1223)

* small refactor

* a printer for a pattern where a condition forks into a space or an indented line prepending the same item

* a printer for a pattern where a group is followed by an indentIfBreak pointing to said group.

* standardising `printPreservingEmptyLines`

* automatically set `grouped: false` when the `firstSeparator` is a `hardline`

* unnecessary group since the contents are already being grouped

* `expression` is not that complicated that it deserves its own function

* more accurate return types for printers

* storing document in const

* preserve empty lines between dangling comments

* only attempt to print the dangling comments if there are no items to be printed

Author: Janther

src/common/printer-helpers.js

@@ -5,19 +5,33 @@ const { isNextLineEmpty } = util;
 
 export const printComments = (node, path, options, filter = () => true) => {
   if (!node.comments) return '';
+  function isPrintable(comment) {
+    return (
+      !comment.trailing &&
+      !comment.leading &&
+      !comment.printed &&
+      filter(comment)
+    );
+  }
   const document = join(
     line,
     path
-      .map((commentPath) => {
+      .map((commentPath, index, comments) => {
         const comment = commentPath.getValue();
-        if (comment.trailing || comment.leading || comment.printed) {
-          return null;
-        }
-        if (!filter(comment)) {
+        if (!isPrintable(comment)) {
           return null;
         }
         comment.printed = true;
-        return options.printer.printComment(commentPath, options);
+        const isLast =
+          index === comments.length - 1 ||
+          comments.slice(index + 1).findIndex(isPrintable) === -1;
+        return [
+          options.printer.printComment(commentPath, options),
+          !isLast &&
+          util.isNextLineEmpty(options.originalText, options.locEnd(comment))
+            ? hardline
+            : ''
+        ];
       }, 'comments')
       .filter(Boolean)
   );

src/nodes/SourceUnit.js

@@ -1,11 +1,15 @@
 import { doc } from 'prettier';
-import { printPreservingEmptyLines } from '../common/printer-helpers.js';
+import {
+  printComments,
+  printPreservingEmptyLines
+} from '../common/printer-helpers.js';
 
 const { line } = doc.builders;
 
 export const SourceUnit = {
-  print: ({ options, path, print }) => [
+  print: ({ node, options, path, print }) => [
     printPreservingEmptyLines(path, 'children', options, print),
+    printComments(node, path, options),
     options.parentParser ? '' : line
   ]
 };

src/slang-comments/handlers/handle-source-unit-members-comments.ts

@@ -0,0 +1,28 @@
+import { NonterminalKind } from '@nomicfoundation/slang/cst';
+import addCollectionFirstComment from './add-collection-first-comment.js';
+import addCollectionLastComment from './add-collection-last-comment.js';
+
+import type { HandlerParams } from './types.js';
+
+export default function handleSourceUnitMembersComments({
+  precedingNode,
+  followingNode,
+  comment
+}: HandlerParams): boolean {
+  if (
+    followingNode &&
+    followingNode.kind === NonterminalKind.SourceUnitMembers
+  ) {
+    addCollectionFirstComment(followingNode, comment);
+    return true;
+  }
+  if (
+    precedingNode &&
+    precedingNode.kind === NonterminalKind.SourceUnitMembers
+  ) {
+    addCollectionLastComment(precedingNode, comment);
+    return true;
+  }
+
+  return false;
+}

src/slang-comments/handlers/index.ts

@@ -8,6 +8,7 @@ import handleLibraryDefinitionComments from './handle-library-definition-comment
 import handleModifierInvocationComments from './handle-modifier-invocation-comments.js';
 import handleParametersDeclarationComments from './handle-parameters-declaration-comments.js';
 import handlePositionalArgumentsDeclarationComments from './handle-positional-arguments-declaration-comments.js';
+import handleSourceUnitMembersComments from './handle-source-unit-members-comments.js';
 import handleStorageLayoutSpecifierComments from './handle-storage-layout-specifier-comments.js';
 import handleStructComments from './handle-struct-comments.js';
 import handleWhileStatementComments from './handle-while-statement-comments.js';
@@ -24,6 +25,7 @@ export default [
   handleModifierInvocationComments,
   handleParametersDeclarationComments,
   handlePositionalArgumentsDeclarationComments,
+  handleSourceUnitMembersComments,
   handleStorageLayoutSpecifierComments,
   handleStructComments,
   handleWhileStatementComments,

src/slang-nodes/AddressType.ts

@@ -1,5 +1,4 @@
 import { NonterminalKind } from '@nomicfoundation/slang/cst';
-import { joinExisting } from '../slang-utils/join-existing.js';
 import { SlangNode } from './SlangNode.js';
 
 import type * as ast from '@nomicfoundation/slang/ast';
@@ -17,6 +16,6 @@ export class AddressType extends SlangNode {
   }
 
   print(): Doc {
-    return joinExisting(' ', ['address', this.payableKeyword]);
+    return ['address', this.payableKeyword ? ' payable' : ''];
   }
 }

src/slang-nodes/ArrayExpression.ts

@@ -1,4 +1,3 @@
-import { doc } from 'prettier';
 import { NonterminalKind } from '@nomicfoundation/slang/cst';
 import { SlangNode } from './SlangNode.js';
 import { ArrayValues } from './ArrayValues.js';
@@ -8,8 +7,6 @@ import type { AstPath, Doc, ParserOptions } from 'prettier';
 import type { AstNode } from './types.d.ts';
 import type { PrintFunction } from '../types.d.ts';
 
-const { group } = doc.builders;
-
 export class ArrayExpression extends SlangNode {
   readonly kind = NonterminalKind.ArrayExpression;
 
@@ -24,6 +21,6 @@ export class ArrayExpression extends SlangNode {
   }
 
   print(path: AstPath<ArrayExpression>, print: PrintFunction): Doc {
-    return group(['[', path.call(print, 'items'), ']']);
+    return ['[', path.call(print, 'items'), ']'];
   }
 }

src/slang-nodes/AssignmentExpression.ts

@@ -1,6 +1,6 @@
 import { NonterminalKind, TerminalKind } from '@nomicfoundation/slang/cst';
-import { doc } from 'prettier';
 import { isBinaryOperation } from '../slang-utils/is-binary-operation.js';
+import { printIndentedGroupOrSpacedDocument } from '../slang-printers/print-indented-group-or-spaced-document.js';
 import { SlangNode } from './SlangNode.js';
 import { Expression } from './Expression.js';
 
@@ -9,8 +9,6 @@ import type { AstPath, Doc, ParserOptions } from 'prettier';
 import type { AstNode } from './types.d.ts';
 import type { PrintFunction } from '../types.d.ts';
 
-const { group, indent, line } = doc.builders;
-
 export class AssignmentExpression extends SlangNode {
   readonly kind = NonterminalKind.AssignmentExpression;
 
@@ -32,14 +30,14 @@ export class AssignmentExpression extends SlangNode {
 
   print(path: AstPath<AssignmentExpression>, print: PrintFunction): Doc {
     const rightOperandVariant = this.rightOperand.variant;
-    const rightOperand = path.call(print, 'rightOperand');
     return [
       path.call(print, 'leftOperand'),
       ` ${this.operator}`,
-      rightOperandVariant.kind !== TerminalKind.Identifier &&
-      isBinaryOperation(rightOperandVariant)
-        ? group(indent([line, rightOperand]))
-        : [' ', rightOperand]
+      printIndentedGroupOrSpacedDocument(
+        path.call(print, 'rightOperand'),
+        rightOperandVariant.kind !== TerminalKind.Identifier &&
+          isBinaryOperation(rightOperandVariant)
+      )
     ];
   }
 }

src/slang-nodes/ContractMembers.ts

@@ -1,7 +1,6 @@
 import { doc } from 'prettier';
 import { NonterminalKind } from '@nomicfoundation/slang/cst';
 import { printSeparatedItem } from '../slang-printers/print-separated-item.js';
-import { printComments } from '../slang-printers/print-comments.js';
 import { printPreservingEmptyLines } from '../slang-printers/print-preserving-empty-lines.js';
 import { SlangNode } from './SlangNode.js';
 import { ContractMember } from './ContractMember.js';
@@ -31,14 +30,10 @@ export class ContractMembers extends SlangNode {
     print: PrintFunction,
     options: ParserOptions<AstNode>
   ): Doc {
-    return this.items.length === 0 && this.comments.length === 0
-      ? ''
-      : printSeparatedItem(
-          [
-            printPreservingEmptyLines(path, print, options),
-            printComments(path)
-          ],
-          { firstSeparator: hardline, grouped: false }
-        );
+    return this.items.length > 0 || this.comments.length > 0
+      ? printSeparatedItem(printPreservingEmptyLines(path, print, options), {
+          firstSeparator: hardline
+        })
+      : '';
   }
 }

src/slang-nodes/ElseBranch.ts

@@ -1,6 +1,6 @@
-import { doc } from 'prettier';
 import { NonterminalKind } from '@nomicfoundation/slang/cst';
 import { createKindCheckFunction } from '../slang-utils/create-kind-check-function.js';
+import { printIndentedGroupOrSpacedDocument } from '../slang-printers/print-indented-group-or-spaced-document.js';
 import { SlangNode } from './SlangNode.js';
 import { Statement } from './Statement.js';
 
@@ -9,8 +9,6 @@ import type { AstPath, Doc, ParserOptions } from 'prettier';
 import type { AstNode } from './types.d.ts';
 import type { PrintFunction } from '../types.d.ts';
 
-const { group, indent, line } = doc.builders;
-
 const isIfStatementOrBlock = createKindCheckFunction([
   NonterminalKind.Block,
   NonterminalKind.IfStatement
@@ -30,12 +28,12 @@ export class ElseBranch extends SlangNode {
   }
 
   print(path: AstPath<ElseBranch>, print: PrintFunction): Doc {
-    const body = path.call(print, 'body');
     return [
       'else',
-      isIfStatementOrBlock(this.body.variant)
-        ? [' ', body]
-        : group(indent([line, body]))
+      printIndentedGroupOrSpacedDocument(
+        path.call(print, 'body'),
+        !isIfStatementOrBlock(this.body.variant)
+      )
     ];
   }
 }

src/slang-nodes/EventDefinition.ts

@@ -32,8 +32,7 @@ export class EventDefinition extends SlangNode {
       'event ',
       path.call(print, 'name'),
       path.call(print, 'parameters'),
-      this.anonymousKeyword ? ' anonymous' : '',
-      ';'
+      this.anonymousKeyword ? ' anonymous;' : ';'
     ];
   }
 }