From 3f246bba3ebb8c9df888a65ceca0ee96f597c051 Mon Sep 17 00:00:00 2001
From: Ian Moffett <ian@osmora.org>
Date: Wed, 1 Oct 2025 18:38:59 -0400
Subject: np: parse: Parse procedure signature

Signed-off-by: Ian Moffett <ian@osmora.org>
---
 src/sys/include/np/ast.h   |  15 +++++++
 src/sys/np/core/np_parse.c | 106 ++++++++++++++++++++++++++++++++++++++-------
 2 files changed, 106 insertions(+), 15 deletions(-)

(limited to 'src')

diff --git a/src/sys/include/np/ast.h b/src/sys/include/np/ast.h
index 9647f53..8e516d7 100644
--- a/src/sys/include/np/ast.h
+++ b/src/sys/include/np/ast.h
@@ -36,6 +36,21 @@
 #include <lib/ptrbox.h>
 #include <string.h>
 
+/*
+ * Valid program integer types
+ */
+typedef enum {
+    AST_BAD_TYPE,
+    AST_U8,
+    AST_U16,
+    AST_U32,
+    AST_U64,
+    AST_I8,
+    AST_I16,
+    AST_I32,
+    AST_I64
+} ast_itype_t;
+
 /*
  * Represents an AST node
  *
diff --git a/src/sys/np/core/np_parse.c b/src/sys/np/core/np_parse.c
index c560294..e72fa4e 100644
--- a/src/sys/np/core/np_parse.c
+++ b/src/sys/np/core/np_parse.c
@@ -124,6 +124,96 @@ parse_expect(struct np_work *work, char *cur, tt_t what, struct lex_token *tok)
     return tt;
 }
 
+/*
+ * Parse a type token
+ *
+ * @work: Current work
+ * @tok: Token result
+ *
+ * Returns the ast integer type on success, and AST_BAD_TYPE
+ * on failure.
+ */
+static ast_itype_t
+parse_type(struct np_work *work, struct lex_token *tok)
+{
+    tt_t tt;
+
+    if (work == NULL || tok == NULL) {
+        return AST_BAD_TYPE;
+    }
+
+    tt = parse_scan(work, tok);
+    switch (tt) {
+    /* Unsigned types */
+    case TT_U8: return AST_U8;
+    case TT_U16: return AST_U16;
+    case TT_U32: return AST_U32;
+    case TT_U64: return AST_U64;
+    }
+
+    return AST_BAD_TYPE;
+}
+
+/*
+ * Parse a procedure / function
+ *
+ * @work: Input work
+ * @tok: Current token
+ *
+ * Returns zero on success
+ */
+static int
+parse_proc(struct np_work *work, struct lex_token *tok)
+{
+    tt_t tt;
+
+    if (work == NULL || tok == NULL) {
+        return -EINVAL;
+    }
+
+    /* We need the identifier */
+    tt = parse_expect(work, "proc", TT_IDENT, tok);
+    if (tt == TT_NONE) {
+        return -1;
+    }
+
+    /* Expect the left paren */
+    tt = parse_expect(work, "<TT_IDENT>", TT_LPAREN, tok);
+    if (tt == TT_NONE) {
+        return -1;
+    }
+
+    /* TODO: ARGS LATER */
+    tt = parse_expect(work, "<TT_LPAREN>", TT_RPAREN, tok);
+    if (tt == TT_NONE) {
+        return -1;
+    }
+
+    /* We need the first part of '->' */
+    tt = parse_expect(work, "<TT_RPAREN>", TT_MINUS, tok);
+    if (tok == TT_NONE) {
+        return -1;
+    }
+
+    /* Now we need to complete the '->' with '>' */
+    tt = parse_expect(work, "<TT_MINUS>", TT_GT, tok);
+    if (tok == TT_NONE) {
+        return -1;
+    }
+
+    /* And now the return type */
+    if (parse_type(work, tok) == AST_BAD_TYPE) {
+        pr_error(
+            "line %d: expected valid type, got %s\n",
+            work->line_no,
+            stoktab[tok->token]
+        );
+        return -1;
+    }
+
+    return 0;
+}
+
 /*
  * Parse a token
  *
@@ -143,21 +233,7 @@ parse_token(struct np_work *work, struct lex_token *tok)
      */
     switch (tok->token) {
     case TT_PROC:
-        /* We need the identifier */
-        tt = parse_expect(work, "proc", TT_IDENT, tok);
-        if (tt == TT_NONE) {
-            return -1;
-        }
-
-        /* Expect the left paren */
-        tt = parse_expect(work, "<TT_IDENT>", TT_LPAREN, tok);
-        if (tt == TT_NONE) {
-            return -1;
-        }
-
-        /* TODO: ARGS LATER */
-        tt = parse_expect(work, "<TT_LPAREN>", TT_RPAREN, tok);
-        if (tt == TT_NONE) {
+        if ((error = parse_proc(work, tok)) != 0) {
             return -1;
         }
         break;
-- 
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