builtin_match_signatures (#1)

Co-authored-by: Lizzy Hunt <lizzy.hunt@usu.edu>
Reviewed-on: https://git.simponic.xyz/simponic/cps-interpreter/pulls/1
Co-authored-by: Elizabeth Hunt <elizabeth.hunt@simponic.xyz>
Co-committed-by: Elizabeth Hunt <elizabeth.hunt@simponic.xyz>

1 files changed, 93 insertions, 0 deletions

diff --git a/src/interpreter/denotable.ts b/src/interpreter/denotable.ts
new file mode 100644
index 0000000..65aee86
--- /dev/null
+++ b/src/interpreter/denotable.ts
@@ -0,0 +1,93 @@
+import type { Identifier } from '@/parser';
+import { testingLogger } from '@t/logger';
+
+export type UnionDenotableType =
+  | Array<DenotableType | DenotableFunctionSignature>
+  | DenotableType
+  | DenotableFunctionSignature
+  | Array<UnionDenotableType>;
+
+export type DenotableFunctionSignature = {
+  arguments: Array<UnionDenotableType>;
+  return: DenotableType;
+};
+
+export type DenotableFunction = {
+  signatures: Array<DenotableFunctionSignature>;
+  body: Function;
+};
+
+export type DenotableType =
+  | 'null'
+  | 'int'
+  | 'real'
+  | 'string'
+  | 'bytearray'
+  | 'function'
+  | 'reference';
+
+export type DenotableValue =
+  | null
+  | number
+  | string
+  | Uint8Array
+  | DenotableFunction
+  | Identifier;
+
+export type Denotable = {
+  type: DenotableType;
+  value: DenotableValue;
+};
+
+export const denotableTypesEquivalent = (
+  a: UnionDenotableType,
+  b: UnionDenotableType,
+): boolean => {
+  if (typeof a !== typeof b) return false;
+
+  if (Array.isArray(a) && Array.isArray(b)) {
+    if (a.length !== b.length) return false;
+    for (let i = 0; i < a.length; i++) {
+      if (!denotableTypesEquivalent(a[i], b[i])) return false;
+    }
+    return true;
+  }
+
+  if (
+    typeof a === 'object' &&
+    typeof b === 'object' &&
+    'arguments' in a &&
+    'arguments' in b
+  ) {
+    if (a.arguments.length !== b.arguments.length) return false;
+    if (!denotableTypesEquivalent(a.return, b.return)) return false;
+    for (let i = 0; i < a.arguments.length; i++) {
+      if (!denotableTypesEquivalent(a.arguments[i], b.arguments[i])) {
+        return false;
+      }
+    }
+    return true;
+  }
+
+  if (a === b) return true;
+
+  return false;
+};
+
+export const matchSignature = (
+  args: Array<UnionDenotableType>,
+  signatures: Array<DenotableFunctionSignature>,
+): DenotableFunctionSignature | undefined => {
+  return signatures.find(signature => {
+    if (args.length !== signature.arguments.length) return false;
+
+    return args.every((arg, i) => {
+      const argSignature = signature.arguments[i];
+      if (Array.isArray(argSignature)) {
+        return argSignature.some(a => denotableTypesEquivalent(a, arg));
+      }
+
+      return denotableTypesEquivalent(arg, signature.arguments[i]);
+    });
+  });
+};