[compiler] Parse and print procedure declarations

Signed-off-by: Quinn Stephens <quinn@osmora.org>

2 files changed, 148 insertions, 0 deletions

diff --git a/compiler/parser/parser.c b/compiler/parser/parser.c
index a630e37..7ee3270 100644
--- a/compiler/parser/parser.c
+++ b/compiler/parser/parser.c
@@ -12,6 +12,7 @@
 #include "debug.h"
 #include "hashmap.h"
 #include "parser/type.h"
+#include "parser/proc.h"
 #include "parser.h"
 
 static void
@@ -62,6 +63,9 @@ parser_parse(struct parser *ctx)
     next_token(ctx);
     while (ctx->tok.kind != TK_EOF) {
         switch (ctx->tok.kind) {
+        case TK_PROC:
+            parse_proc(ctx);
+            break;
         case TK_TYPE:
             parse_type(ctx);
             break;
diff --git a/compiler/parser/proc.c b/compiler/parser/proc.c
new file mode 100644
index 0000000..bbbdad1
--- /dev/null
+++ b/compiler/parser/proc.c
@@ -0,0 +1,144 @@
+/*
+ * Procedure parser.
+ * Copyright (c) 2023-2024, Quinn Stephens and the OSMORA team.
+ * Provided under the BSD 3-Clause license.
+ */
+
+#include <stdbool.h>
+#include "debug.h"
+#include "parser/proc.h"
+#include "parser/type.h"
+#include "parser.h"
+
+#define HASHMAP_ROWS 8
+
+static bool
+parse_params(struct parser *ctx, struct procedure *proc)
+{
+    struct parameter *param;
+    struct variable *var;
+    struct type *typ;
+    int n_ptrs;
+
+    debug("Parsing procedure parameters...\n");
+
+    while (ctx->tok.kind != TK_RPAREN) {
+        if (ctx->tok.kind != TK_IDENTIFIER) {
+            tok_error(&ctx->tok, "expected parameter type name or \")\"\n");
+            return false;
+        }
+
+        if (!parse_type_ref(ctx, &typ, &n_ptrs)) {
+            return false;
+        }
+
+        if (ctx->tok.kind != TK_IDENTIFIER) {
+            tok_error(&ctx->tok, "expected parameter name\n");
+            return false;
+        }
+
+        param = malloc(sizeof(struct parameter));
+        var = &param->var;
+        var->hashmap_entry.hash = ctx->tok.hash;
+        var->name = ctx->tok.pos;
+        var->name_len = ctx->tok.len;
+        var->typ = typ;
+        var->n_ptrs = n_ptrs;
+        hashmap_add(&proc->vars, &var->hashmap_entry);
+        list_append(&proc->params, &param->list_entry);
+
+        if (next_token(ctx)->kind == TK_COMMA && next_token(ctx)->kind == TK_RPAREN) {
+            tok_warn(&ctx->tok, "extra \",\" at end of parameter list\n");
+        }
+    }
+    next_token(ctx);
+
+    return true;
+}
+
+void
+parse_proc(struct parser *ctx)
+{
+    struct procedure *proc;
+
+    debug("Parsing procedure declaration...\n");
+
+    /* Procedure name */
+    if (next_token(ctx)->kind != TK_IDENTIFIER) {
+        tok_error(&ctx->tok, "expected identifier after \"proc\"\n");
+        return;
+    }
+
+    /* Ensure procedure does not already exist */
+    proc = (struct procedure*)hashmap_find(ctx->procs, ctx->tok.hash);
+    if (proc != NULL) {
+        tok_error(&ctx->tok, "procedure \"%.*s\" already declared\n", (int)ctx->tok.len, ctx->tok.pos);
+        return;
+    }
+
+    /* Create procedure */
+    proc = malloc(sizeof(struct procedure));
+    proc->hashmap_entry.hash = ctx->tok.hash;
+    proc->name = ctx->tok.pos;
+    proc->name_len = ctx->tok.len;
+
+    if (next_token(ctx)->kind != TK_LPAREN) {
+        tok_error(&ctx->tok, "expected \"(\" after procedure name\n");
+        free(proc);
+        return;
+    }
+
+    /* Set up variables hashmap */
+    proc->vars.rows = malloc(HASHMAP_ROWS * sizeof(struct list));
+    proc->vars.n_rows = HASHMAP_ROWS;
+    hashmap_init(&proc->vars);
+
+    /* Set up parameter list */
+    list_init(&proc->params);
+
+    /* Parse parameters */
+    if (next_token(ctx)->kind != TK_RPAREN) {
+        if (!parse_params(ctx, proc)) {
+            hashmap_free_entries(&proc->vars);
+            free(proc->vars.rows);
+            free(proc);
+            return;
+        }
+    } else {
+        next_token(ctx);
+    }
+
+    /* Parse return type if specified */
+    if (ctx->tok.kind == TK_ARROW) {
+        next_token(ctx);
+        if (!parse_type_ref(ctx, &proc->ret_typ, &proc->ret_n_ptrs)) {
+            hashmap_free_entries(&proc->vars);
+            free(proc->vars.rows);
+            free(proc);
+            return;
+        }
+    }
+
+    /* Add procedure to parser's registry */
+    hashmap_add(ctx->procs, &proc->hashmap_entry);
+
+    /* We are finished now if this is just a declaration */
+    if (ctx->tok.kind == TK_SEMICOLON) {
+        next_token(ctx);
+        return;
+    }
+
+    if (ctx->tok.kind != TK_LBRACE) {
+        tok_error(&ctx->tok, "Expected \";\" or \"{\"\n");
+        return;
+    }
+
+    /* TODO: Parse body/code */
+
+    if (next_token(ctx)->kind != TK_RBRACE) {
+        tok_error(&ctx->tok, "Expected \"}\" after procedure body\n");
+        return;
+    }
+
+    next_token(ctx);
+}