Fix nested subscripts parsing #114

packages/unified-latex-util-parse/tests/parse.test.ts

@@ -5,6 +5,8 @@ import { trimRenderInfo } from "@unified-latex/unified-latex-util-render-info";
 import * as Ast from "@unified-latex/unified-latex-types/index";
 import { trim } from "@unified-latex/unified-latex-util-trim";
 import { processLatexToAstViaUnified } from "@unified-latex/unified-latex";
+import { PluginOptions as ParserPluginOptions } from "../libs/plugin-from-string";
+import * as AstBuilder from "@unified-latex/unified-latex-builder";
 
 /* eslint-env jest */
 
@@ -18,9 +20,9 @@ describe("unified-latex-util-parse", () => {
     let value: string | undefined;
     let file: VFile | undefined;
 
-    function strToNodes(str: string) {
+    function strToNodes(str: string, options?: ParserPluginOptions) {
         value = str;
-        file = processLatexToAstViaUnified().processSync({ value });
+        file = processLatexToAstViaUnified(options).processSync({ value });
         const root = trimRenderInfo(file.result as any) as Ast.Root;
         return root.content;
     }
@@ -73,4 +75,44 @@ describe("unified-latex-util-parse", () => {
         trim(ast);
         expect(ast).toEqual(targetAst);
     });
+
+    it("nested math subscripts", () => {
+        let ast = strToNodes("{1_2}", {
+            mode: 'math',
+        });
+        expect(ast).toEqual([{
+            type: "group",
+            content: [
+                AstBuilder.s("1"),
+                AstBuilder.m("_", AstBuilder.args([
+                    AstBuilder.arg([AstBuilder.s("2")], {
+                        openMark: '{',
+                        closeMark: '}',
+                    }),
+                ]), { escapeToken: "" }),
+            ],
+        }]);
+    });
+
+    it("nested math single char arguments", () => {
+        const ast = strToNodes("{\\frac12}", {
+            mode: "math",
+        });
+        expect(ast).toEqual([{
+            type: "group",
+            content: [
+                AstBuilder.m('frac', AstBuilder.args([
+                    AstBuilder.arg([AstBuilder.s("1")], {
+                        openMark: '{',
+                        closeMark: '}',
+                    }),
+                    AstBuilder.arg([AstBuilder.s("2")], {
+                        openMark: '{',
+                        closeMark: '}',
+                    }),
+                ])),
+            ],
+        }]);
+
+    });
 });

packages/unified-latex-util-pegjs/grammars/latex.pegjs

@@ -69,7 +69,7 @@ math_token "math token"
     = special_macro
     / macro
     / full_comment
-    / whitespace* x:group whitespace* { return x; }
+    / whitespace* x:math_group whitespace* { return x; }
     / whitespace* x:alignment_tab whitespace* { return x; }
     / macro_parameter
     / whitespace* superscript whitespace* {

packages/unified-latex/libs/unified-latex.ts

@@ -28,6 +28,8 @@ export const processLatexViaUnified = (
  * Use `unified()` to a string to an `Ast.Ast` and then return it. This function
  * will not print/pretty-print the `Ast.Ast` back to a string.
  */
-export const processLatexToAstViaUnified = () => {
-    return unified().use(unifiedLatexFromString).use(unifiedLatexAstComplier);
+export const processLatexToAstViaUnified = (
+    options?: ParserPluginOptions
+) => {
+    return unified().use(unifiedLatexFromString, options).use(unifiedLatexAstComplier);
 };