From e9f3c782bc10d4c5c44faf768aa60cd6bcc66574 Mon Sep 17 00:00:00 2001
From: Kai Stevenson <kai@kaistevenson.com>
Date: Sun, 2 Nov 2025 18:08:16 -0800
Subject: refactor

---
 src/lang/core/parser.ts | 220 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 220 insertions(+)
 create mode 100644 src/lang/core/parser.ts

(limited to 'src/lang/core/parser.ts')

diff --git a/src/lang/core/parser.ts b/src/lang/core/parser.ts
new file mode 100644
index 0000000..79218e9
--- /dev/null
+++ b/src/lang/core/parser.ts
@@ -0,0 +1,220 @@
+import {
+  ASTNode,
+  NodeType,
+  ParserCtx,
+  Token,
+  TokenSubType,
+  TokenType,
+} from "./common";
+import { Lex } from "./lexer";
+
+/* 
+start
+if no 'lastName'
+then:
+    expect nextToken to be a name
+    lastName = nextToken
+    goto start
+    
+else:
+    if nextToken is name
+    then:
+        // we already have a lastName
+        mutate last element of stack to push lastName as child
+        lastName = nextToken
+        goto start
+
+    else:
+        //nextToken is openParen or close paren
+        if nextToken is closeParen
+        then:
+            set last element of stack as child of prev element on stack
+            pop stack
+            // [stack[last - 1].children.push(stack.pop)
+            goto start
+        else if nextToken is openParen:
+            push lastName onto stack
+            goto start
+
+
+finally:
+    // only one element remains on the stack
+    return stack[0]
+
+
+    CALL ( param, CALL2 ( param2 ) )
+
+    param2 ret call2 param ret call
+
+    | call
+    |-- param
+    |-- | call2
+        |-- param2
+
+ */
+
+export type Error<T extends string> = ASTNode<
+  NodeType.PARSER_ERROR,
+  "Error",
+  T,
+  []
+>;
+
+export type PushChild<Node extends ASTNode, Child extends ASTNode> = {
+  type: Node["type"];
+  value: Node["value"];
+  name: Node["name"];
+  children: [...Node["children"], Child];
+};
+
+export type PushChildToLastElementOfStack<
+  Stack extends ParserCtx["stack"],
+  Child extends ASTNode
+> = Stack extends [...infer Head, infer Tail extends ASTNode]
+  ? [...Head, PushChild<Tail, Child>]
+  : Stack extends [infer Only extends ASTNode]
+  ? [PushChild<Only, Child>]
+  : never;
+
+export type PushChildToSecondLastElementOfStack<
+  Stack extends ParserCtx["stack"],
+  Child extends ASTNode
+> = Stack extends [
+  ...infer Head,
+  infer Tail extends ASTNode,
+  infer Final extends ASTNode
+]
+  ? [...Head, PushChild<Tail, Child>, Final]
+  : Stack extends [infer Only extends ASTNode, infer Final extends ASTNode]
+  ? [PushChild<Only, Child>, Final]
+  : never;
+
+export type GetLastOnStack<Stack extends ParserCtx["stack"]> = Stack extends [
+  ...infer Head,
+  infer Tail extends ASTNode
+]
+  ? Tail
+  : Stack extends [infer Only extends ASTNode]
+  ? Only
+  : never;
+
+export type StackWithoutLast<Stack extends ParserCtx["stack"]> = Stack extends [
+  ...infer Head extends ASTNode[],
+  infer Tail
+]
+  ? [...Head]
+  : Stack extends [infer Only extends ASTNode]
+  ? []
+  : never;
+
+type NULL_SENTINEL = {
+  NULL: true;
+};
+
+export type ParseNumberLiteral<T extends string> =
+  T extends `${infer Inner extends number}` ? Inner : NULL_SENTINEL;
+
+export type ParseStringLiteral<T extends string> =
+  T extends `"${infer Inner extends string}"` ? Inner : NULL_SENTINEL;
+
+export type ResolveNodeFromToken<_Token extends Token> = ParseNumberLiteral<
+  _Token["name"]
+> extends number
+  ? ASTNode<NodeType.INT, "", ParseNumberLiteral<_Token["name"]>, []>
+  : ParseStringLiteral<_Token["name"]> extends string
+  ? ASTNode<NodeType.INT, "", ParseStringLiteral<_Token["name"]>, []>
+  : ASTNode<NodeType.EXT, _Token["name"], null, []>;
+
+export type _Parse<Ctx extends ParserCtx> = Ctx["remainingTokens"] extends [
+  infer Head extends Token,
+  ...infer Tail extends readonly Token[]
+]
+  ? Ctx["lastToken"] extends Token
+    ? Head["type"] extends TokenType.NAME
+      ? // we already have a lastName
+        // mutate last element of stack to push lastName as child
+        // lastName = nextToken
+        // goto start
+        _Parse<{
+          lastToken: Head;
+          remainingTokens: Tail;
+          stack: PushChildToLastElementOfStack<
+            Ctx["stack"],
+            ResolveNodeFromToken<Ctx["lastToken"]>
+          >;
+        }>
+      : //nextToken is openParen or close paren
+      Head["type"] extends TokenType.CLOSE_PAREN
+      ? // handle lastName
+        // set last element of stack as child of prev element on stack
+        // pop stack
+        // [stack[last - 1].children.push(stack.pop)
+        // goto start
+        _Parse<{
+          lastToken: null;
+          remainingTokens: Tail;
+          // first push the last name onto the children of the top
+          // then push the top onto the children of the next
+          // then remove the top
+          stack: StackWithoutLast<
+            PushChildToSecondLastElementOfStack<
+              Ctx["stack"],
+              PushChild<
+                GetLastOnStack<Ctx["stack"]>,
+                ResolveNodeFromToken<Ctx["lastToken"]>
+              >
+            >
+          >;
+        }>
+      : Head["type"] extends TokenType.OPEN_PAREN
+      ? // push lastName onto stack
+        // goto start
+        _Parse<{
+          lastToken: null;
+          remainingTokens: Tail;
+          stack: [...Ctx["stack"], ResolveNodeFromToken<Ctx["lastToken"]>];
+        }>
+      : Ctx & Error<`Was not expecting ${Head["type"]}`>
+    : // expect nextToken to be a name or close paren
+    Head["type"] extends TokenType.NAME
+    ? // lastName = nextToken
+      // goto start
+      _Parse<{
+        lastToken: Head;
+        remainingTokens: Tail;
+        stack: Ctx["stack"];
+      }>
+    : Head["type"] extends TokenType.CLOSE_PAREN
+    ? _Parse<{
+        lastToken: null;
+        remainingTokens: Tail;
+        // push the top onto the children of the next
+        // then remove the top
+        stack: StackWithoutLast<
+          PushChildToSecondLastElementOfStack<
+            Ctx["stack"],
+            GetLastOnStack<Ctx["stack"]>
+          >
+        >;
+      }>
+    : Ctx &
+        Error<`Expected nextToken to be a name or close paren at ${Head["type"]}`>
+  : Ctx["lastToken"] extends Token
+  ? // case where we ended with a name
+    _Parse<{
+      lastToken: null;
+      remainingTokens: [];
+      stack: PushChildToLastElementOfStack<
+        Ctx["stack"],
+        ResolveNodeFromToken<Ctx["lastToken"]>
+      >;
+    }>
+  : Ctx["stack"][0];
+
+export type Parse<Raw extends readonly Token[]> = _Parse<{
+  lastToken: null;
+  remainingTokens: Raw;
+  stack: [ASTNode<NodeType.EXT, "arr", null, []>];
+}>;
+
+const test_result = null as unknown as Parse<Lex<`test(135)`>>;
-- 
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