Update bnf binding for js.

Author: hzhangxyz

bnf/atsds_bnf/index.js

@@ -1,10 +1,107 @@
-/**
- * BNF Parser and Unparsers for DS
- * 
- * This package provides bidirectional conversion between:
- * - Ds: The lisp-like syntax currently used in DS
- * - Dsp: A traditional readable syntax
- */
-
-export { unparse } from './unparse.js';
-export { parse } from './parse.js';
+import {
+    InputStream,
+    CommonTokenStream
+} from "antlr4";
+import DspLexer from "./DspLexer.js";
+import DspParser from "./DspParser.js";
+import DspVisitor from "./DspVisitor.js";
+import DsLexer from "./DsLexer.js";
+import DsParser from "./DsParser.js";
+import DsVisitor from "./DsVisitor.js";
+
+class ParseVisitor extends DspVisitor {
+    visitRule_pool(ctx) {
+        return ctx.rule_().map(r => this.visit(r)).join("\n\n");
+    }
+
+    visitRule(ctx) {
+        const result = ctx.term().map(t => this.visit(t));
+        if (result.length === 1) {
+            return `----\n${result[0]}`;
+        } else {
+            const conclusion = result.pop();
+            const length = Math.max(...result.map(premise => premise.length));
+            result.push("-".repeat(Math.max(length, 4)));
+            result.push(conclusion);
+            return result.join("\n");
+        }
+    }
+
+    visitSymbol(ctx) {
+        return ctx.SYMBOL().getText();
+    }
+
+    visitParentheses(ctx) {
+        return this.visit(ctx.term());
+    }
+
+    visitSubscript(ctx) {
+        return `(subscript ${ctx.term().map(t => this.visit(t)).join(" ")})`;
+    }
+
+    visitFunction(ctx) {
+        return `(function ${ctx.term().map(t => this.visit(t)).join(" ")})`;
+    }
+
+    visitUnary(ctx) {
+        return `(unary ${ctx.getChild(0).getText()} ${this.visit(ctx.term())})`;
+    }
+
+    visitBinary(ctx) {
+        return `(binary ${ctx.getChild(1).getText()} ${this.visit(ctx.term(0))} ${this.visit(ctx.term(1))})`;
+    }
+}
+
+
+class UnparseVisitor extends DsVisitor {
+    visitRule_pool(ctx) {
+        return ctx.rule_().map(r => this.visit(r)).join("\n");
+    }
+
+    visitRule(ctx) {
+        const result = ctx.term().map(t => this.visit(t));
+        const conclusion = result.pop();
+        const length = Math.max(...result.map(premise => premise.length));
+        return result.join(", ") + " -> " + conclusion;
+    }
+
+    visitSymbol(ctx) {
+        return ctx.SYMBOL().getText();
+    }
+
+    visitSubscript(ctx) {
+        return `${this.visit(ctx.term(0))}[${ctx.term().slice(1).map(t => this.visit(t)).join(", ")}]`;
+    }
+
+    visitFunction(ctx) {
+        return `${this.visit(ctx.term(0))}(${ctx.term().slice(1).map(t => this.visit(t)).join(", ")})`;
+    }
+
+    visitUnary(ctx) {
+        return `(${ctx.getChild(0).getText()} ${this.visit(ctx.term())})`;
+    }
+
+    visitBinary(ctx) {
+        return `(${this.visit(ctx.term(0))} ${ctx.getChild(1).getText()} ${this.visit(ctx.term(1))})`;
+    }
+}
+
+export function parse(input) {
+    const chars = new InputStream(input);
+    const lexer = new DspLexer(chars);
+    const tokens = new CommonTokenStream(lexer);
+    const parser = new DspParser(tokens);
+    const tree = parser.rule_pool();
+    const visitor = new ParseVisitor();
+    return visitor.visit(tree);
+}
+
+export function unparse(input) {
+    const chars = new InputStream(input);
+    const lexer = new DsLexer(chars);
+    const tokens = new CommonTokenStream(lexer);
+    const parser = new DsParser(tokens);
+    const tree = parser.rule_pool();
+    const visitor = new UnparseVisitor();
+    return visitor.visit(tree);
+}