add parser

1 files changed, 35 insertions, 0 deletions

diff --git a/src/interpreter/parser.ts b/src/interpreter/parser.ts
new file mode 100644
index 0000000..ea07796
--- /dev/null
+++ b/src/interpreter/parser.ts
@@ -0,0 +1,35 @@
+import peggyParser from "./PeggyParser.js";
+
+export type Application = {
+  application: {
+    left: LambdaTerm;
+    args: Array<LambdaTerm>;
+  };
+};
+
+export type Abstraction = {
+  abstraction: {
+    param: Variable;
+    body: LambdaTerm;
+  };
+};
+
+export type Variable = string;
+
+export type LambdaTerm = Application | Abstraction | Variable;
+
+export const isApplication = (term: LambdaTerm): term is Application => {
+  return (term as Application).application !== undefined;
+};
+
+export const isAbstraction = (term: LambdaTerm): term is Abstraction => {
+  return (term as Abstraction).abstraction !== undefined;
+};
+
+export const isVariable = (term: LambdaTerm): term is Variable => {
+  return typeof term === "string";
+};
+
+export const parse = (term: string) => {
+  return peggyParser.parse(term, { library: true });
+};