feat: support for modifier (#83)

Author: ota-meshi

scripts/update-fixtures.ts

@@ -53,6 +53,8 @@ for (const filename of Object.keys(Visitor.fixturesData)) {
             onExpressionCharacterClassEnter: enter,
             onFlagsEnter: enter,
             onGroupEnter: enter,
+            onModifierFlagsEnter: enter,
+            onModifiersEnter: enter,
             onPatternEnter: enter,
             onQuantifierEnter: enter,
             onRegExpLiteralEnter: enter,
@@ -71,6 +73,8 @@ for (const filename of Object.keys(Visitor.fixturesData)) {
             onExpressionCharacterClassLeave: leave,
             onFlagsLeave: leave,
             onGroupLeave: leave,
+            onModifierFlagsLeave: leave,
+            onModifiersLeave: leave,
             onPatternLeave: leave,
             onQuantifierLeave: leave,
             onRegExpLiteralLeave: leave,

src/ast.ts

@@ -17,6 +17,7 @@ export type BranchNode =
     | ExpressionCharacterClass
     | Group
     | LookaroundAssertion
+    | Modifiers
     | Pattern
     | Quantifier
     | RegExpLiteral
@@ -31,6 +32,7 @@ export type LeafNode =
     | Character
     | CharacterSet
     | Flags
+    | ModifierFlags
 
 /**
  * The type which includes all atom nodes.
@@ -122,6 +124,7 @@ export interface Alternative extends NodeBase {
 export interface Group extends NodeBase {
     type: "Group"
     parent: Alternative | Quantifier
+    modifiers: Modifiers | null
     alternatives: Alternative[]
 }
 
@@ -446,6 +449,36 @@ export interface UnambiguousBackreference extends BaseBackreference {
     resolved: CapturingGroup
 }
 
+/**
+ * The modifiers.
+ */
+export interface Modifiers extends NodeBase {
+    type: "Modifiers"
+    parent: Group
+    /**
+     * The add modifier flags.
+     */
+    add: ModifierFlags
+    /**
+     * The remove modifier flags.
+     *
+     * `null` means no remove modifier flags. e.g. `(?ims:x)`
+     * The reason for `null` is that there is no position where the remove modifier flags appears. Must be behind the minus mark.
+     */
+    remove: ModifierFlags | null
+}
+
+/**
+ * The modifier flags.
+ */
+export interface ModifierFlags extends NodeBase {
+    type: "ModifierFlags"
+    parent: Modifiers
+    dotAll: boolean
+    ignoreCase: boolean
+    multiline: boolean
+}
+
 /**
  * The flags.
  */

src/parser.ts

@@ -18,6 +18,7 @@ import type {
     UnicodeSetsCharacterClass,
     ExpressionCharacterClass,
     StringAlternative,
+    Modifiers,
 } from "./ast"
 import type { EcmaVersion } from "./ecma-versions"
 import { latestEcmaVersion } from "./ecma-versions"
@@ -31,6 +32,7 @@ type AppendableNode =
     | ClassStringDisjunction
     | Group
     | LookaroundAssertion
+    | Modifiers
     | Pattern
     | StringAlternative
 
@@ -205,14 +207,17 @@ class RegExpParserState {
             throw new Error("UnknownError")
         }
 
-        this._node = {
+        const group: Group = {
             type: "Group",
             parent,
             start,
             end: start,
             raw: "",
+            modifiers: null,
             alternatives: [],
         }
+
+        this._node = group
         parent.elements.push(this._node)
     }
 
@@ -227,6 +232,85 @@ class RegExpParserState {
         this._node = node.parent
     }
 
+    public onModifiersEnter(start: number): void {
+        const parent = this._node
+        if (parent.type !== "Group") {
+            throw new Error("UnknownError")
+        }
+
+        this._node = {
+            type: "Modifiers",
+            parent,
+            start,
+            end: start,
+            raw: "",
+            add: null as never, // Set in onAddModifiers.
+            remove: null,
+        }
+        parent.modifiers = this._node
+    }
+
+    public onModifiersLeave(start: number, end: number): void {
+        const node = this._node
+        if (node.type !== "Modifiers" || node.parent.type !== "Group") {
+            throw new Error("UnknownError")
+        }
+
+        node.end = end
+        node.raw = this.source.slice(start, end)
+        this._node = node.parent
+    }
+
+    public onAddModifiers(
+        start: number,
+        end: number,
+        {
+            ignoreCase,
+            multiline,
+            dotAll,
+        }: { ignoreCase: boolean; multiline: boolean; dotAll: boolean },
+    ): void {
+        const parent = this._node
+        if (parent.type !== "Modifiers") {
+            throw new Error("UnknownError")
+        }
+        parent.add = {
+            type: "ModifierFlags",
+            parent,
+            start,
+            end,
+            raw: this.source.slice(start, end),
+            ignoreCase,
+            multiline,
+            dotAll,
+        }
+    }
+
+    public onRemoveModifiers(
+        start: number,
+        end: number,
+        {
+            ignoreCase,
+            multiline,
+            dotAll,
+        }: { ignoreCase: boolean; multiline: boolean; dotAll: boolean },
+    ): void {
+        const parent = this._node
+        if (parent.type !== "Modifiers") {
+            throw new Error("UnknownError")
+        }
+        parent.remove = {
+            type: "ModifierFlags",
+            parent,
+            start,
+            end,
+            raw: this.source.slice(start, end),
+            ignoreCase,
+            multiline,
+            dotAll,
+        }
+    }
+
     public onCapturingGroupEnter(start: number, name: string | null): void {
         const parent = this._node
         if (parent.type !== "Alternative") {
@@ -765,7 +849,7 @@ export namespace RegExpParser {
          * - `2022` added `d` flag.
          * - `2023` added more valid Unicode Property Escapes.
          * - `2024` added `v` flag.
-         * - `2025` added duplicate named capturing groups.
+         * - `2025` added duplicate named capturing groups, modifiers.
          */
         ecmaVersion?: EcmaVersion
     }