✨ feat(vscode): 代码阅读把推导式换成按读的顺序重排的遍历小框

vscode/src/codeReader/languages/python.ts

@@ -1,4 +1,4 @@
-import type { Access, BlockShape, ClassFacts, CodeBlock, EntryFacts, FunctionFacts, ImportFacts, ImportItem, LanguageAdapter, Node, ParameterFacts, TextKind, TokenRole } from '../contract'
+import type { Access, BlockShape, ClassFacts, CodeBlock, EntryFacts, FunctionFacts, ImportFacts, ImportItem, IterationClause, IterationFacts, IterationResult, LanguageAdapter, Node, ParameterFacts, TextKind, TokenRole } from '../contract'
 import type { CommentRules } from './shared'
 import * as path from 'node:path'
 import { children, compoundShape, leafBlock, leafShape, listBlocks, named, sameNode, syntaxChildren } from './shared'
@@ -258,6 +258,54 @@ function dictionaryEntries(value: Node | null): EntryFacts[] | undefined {
   })
 }
 
+const ITERATION_RESULTS: Record<string, IterationResult> = {
+  generator_expression: 'generator',
+  list_comprehension: 'list',
+  set_comprehension: 'set',
+  dictionary_comprehension: 'dict',
+}
+
+/**
+ * 推导式、生成器表达式的结构，别的节点没有。几种读不成遍历的写法也没有，照常翻：
+ * `for x in a, b`（语法树认、Python 3 不认的多个来源），以及缺了变量、来源、条件或每一项的值（写到一半的代码）。
+ */
+export function pythonIteration(node: Node): IterationFacts | undefined {
+  const result = ITERATION_RESULTS[node.type]
+  const body = node.childForFieldName('body')
+  if (!result || !body)
+    return undefined
+  const clauses: IterationClause[] = []
+  for (const child of syntaxChildren(node)) {
+    if (child.type === 'for_in_clause') {
+      const variables = child.childForFieldName('left')
+      const sources = child.childrenForFieldName('right').filter(source => source !== null)
+      if (!variables || sources.length !== 1)
+        return undefined
+      clauses.push({ kind: 'for', variables, source: sources[0], async: child.children.some(token => token?.type === 'async') })
+    }
+    else if (child.type === 'if_clause') {
+      const [condition] = syntaxChildren(child)
+      if (!condition)
+        return undefined
+      clauses.push({ kind: 'if', condition })
+    }
+  }
+  if (clauses[0]?.kind !== 'for')
+    return undefined
+  const key = result === 'dict' ? body.childForFieldName('key') : undefined
+  const value = result === 'dict' ? body.childForFieldName('value') : body
+  if (!value || key === null)
+    return undefined
+  const facts: IterationFacts = { result, clauses, value, ...(key && { key }) }
+  // 调用唯一的参数是生成器表达式时只写一对括号（f(x for x in y)），语法树把这对括号算给生成器
+  const call = node.parent
+  const open = node.child(0)
+  const close = node.child(node.childCount - 1)
+  if (result === 'generator' && call?.type === 'call' && sameNode(call.childForFieldName('arguments'), node) && open && close)
+    facts.sharedParentheses = { open, close }
+  return facts
+}
+
 /** elif / else 展平成紧跟 if 的兄弟块。 */
 function ifBlocks(node: Node): CodeBlock[] {
   const blocks = [bodyBlock('if', node, bodyOf(node), 'other')]