functional type checker

1 files changed, 210 insertions, 5 deletions

diff --git a/type_checker.c b/type_checker.c
index deb3345..538f51d 100644
--- a/type_checker.c
+++ b/type_checker.c
@@ -1,4 +1,4 @@
-#include "ast.h"
+#include "type_checker.h"
 #include "scope.h"
 #include <stdio.h>
 #include <stdlib.h>
@@ -13,15 +13,211 @@
 
 static struct scope* scope;
 
+static void type_check_expr(struct expr_node* node);
+static void type_check_lval(struct lval_node* node);
+static void type_check_stmt(struct stmt_node* node);
 static void type_check_group(struct group_node* node);
 
-static void type_check_expr(struct expr_node* node) {}
+static void assert_cast_compatible(
+    const struct type_def* lval_type,
+    const struct type_def* rval_type
+) {
+    /* TODO: impl */
+    /* TODO: we should also insert cast nodes eventually */
+    if (false) {
+        TYPE_PANIC(
+            "cannot assign value of type '%s' to '%s'",
+            lval_type->key.name,
+            rval_type->key.name);
+    }
+}
+
+static const struct type_def* resolve_type_ref(struct type_ref_node* node) {
+    /* TODO: support pointers and such */
+    if (node->def_ref == NULL) TYPE_PANIC("use of unresolved type");
+    return node->def_ref;
+}
+
+/* TODO: we likely want some shortcut to access char, int, double, long, etc. */
+static const struct type_def* resolve_int_lit(struct int_lit_node* node) {
+    const struct type_def* resolved_type;
+    scope_get_type(scope, &resolved_type, &(struct type_key) {
+        .name = "int",
+        .how_long = 1,
+        .marked_signed = false,
+        .marked_unsigned = false,
+    });
+
+    if (resolved_type == NULL)
+        TYPE_PANIC(
+            "no integral type exists, "
+            "ensure install_default_types was called.");
+
+    return resolved_type;
+}
+
+static const struct type_def* resolve_float_lit(struct float_lit_node* node) {
+    const struct type_def* resolved_type;
+    scope_get_type(scope, &resolved_type, &(struct type_key) {
+        .name = "float",
+        .how_long = 0,
+        .marked_signed = false,
+        .marked_unsigned = false,
+    });
+
+    if (resolved_type == NULL)
+        TYPE_PANIC(
+            "no floating point type exists, "
+            "ensure install_default_types was called.");
+
+    return resolved_type;
+}
+
+static const struct type_def* resolve_char_lit(struct char_lit_node* node) {
+    const struct type_def* resolved_type;
+    scope_get_type(scope, &resolved_type, &(struct type_key) {
+        .name = "char",
+        .how_long = 0,
+        .marked_signed = false,
+        .marked_unsigned = false,
+    });
+
+    if (resolved_type == NULL)
+        TYPE_PANIC(
+            "no character type exists, "
+            "ensure install_default_types was called.");
+
+    return resolved_type;
+}
 
-static void type_check_var_decl(struct var_decl_node* node) {}
+static const struct type_def* resolve_str_lit(struct str_lit_node* node) {
+    /* TODO: pointer types */
+    const struct type_def* resolved_type;
+    scope_get_type(scope, &resolved_type, &(struct type_key) {
+        .name = "int",
+        .how_long = 1,
+        .marked_signed = false,
+        .marked_unsigned = true,
+    });
 
-static void type_check_return(struct return_node* node) {}
+    if (resolved_type == NULL)
+        TYPE_PANIC(
+            "no string type exists, "
+            "ensure install_default_types was called.");
 
-static void type_check_if(struct if_node* node) {}
+    return resolved_type;
+}
+
+static const struct type_def* resolve_var_ref(struct var_ref_node* node) {
+    if (node->def_ref->resolved_type == NULL)
+        TYPE_PANIC("variable '%s' has unresolved type.", node->def_ref->name);
+    return node->def_ref->resolved_type;
+}
+
+static void type_check_var_decl(struct var_decl_node* node) {
+    node->def_ref->resolved_type = resolve_type_ref(&node->type);
+}
+
+static const struct type_def* resolve_assign(struct assign_node* node) {
+    type_check_lval(&node->lval);
+    type_check_expr(node->rval);
+    const struct type_def* lval_type = node->lval.resolved_type;
+    const struct type_def* rval_type = node->rval->resolved_type;
+
+    assert_cast_compatible(lval_type, rval_type);
+    return lval_type;
+}
+
+static const struct type_def* resolve_call(struct call_node* node) {
+    struct args_decl_node* arg_decl = node->called_fn_ref->args;
+    struct args_eval_node* arg_eval = node->args;
+    while (arg_decl != NULL && arg_eval != NULL) {
+        type_check_var_decl(arg_decl->decl);
+        const struct type_def* decl_type =
+            arg_decl->decl->def_ref->resolved_type;
+        type_check_expr(arg_eval->expr);
+        const struct type_def* eval_type = arg_eval->expr->resolved_type;
+        assert_cast_compatible(decl_type, eval_type);
+
+        arg_decl = arg_decl->next;
+        arg_eval = arg_eval->next;
+    }
+    if (arg_decl != NULL || arg_eval != NULL)
+        TYPE_PANIC(
+            "mismatched argument count in call to '%s'",
+            node->called_fn_ref->name);
+
+    return resolve_type_ref(&node->called_fn_ref->return_type);
+}
+
+static const struct type_def* resolve_unary(struct unary_node* node) {
+    type_check_expr(node->expr);
+    /* TODO: delegate by individual operation to prohibit shit like -"yes" */
+    return node->expr->resolved_type;
+}
+
+static const struct type_def* resolve_binary(struct binary_node* node) {
+    /* TODO: math rules and such lol */
+    type_check_expr(node->lhs);
+    type_check_expr(node->rhs);
+    assert_cast_compatible(node->lhs->resolved_type, node->rhs->resolved_type);
+    return node->lhs->resolved_type;
+}
+
+static void type_check_lval(struct lval_node* node) {
+    switch (node->type) {
+        case LVAL_VAR_DECL:
+            type_check_var_decl(&node->inner.var_decl);
+            node->resolved_type = node->inner.var_decl.def_ref->resolved_type;
+            break;
+        case LVAL_VAR_REF:
+            node->resolved_type = resolve_var_ref(&node->inner.var_ref);
+            break;
+    }
+}
+
+static void type_check_expr(struct expr_node* node) {
+    switch (node->type) {
+        case EXPR_INT_LIT:
+            node->resolved_type = resolve_int_lit(&node->inner.int_lit);
+            break;
+        case EXPR_FLOAT_LIT:
+            node->resolved_type = resolve_float_lit(&node->inner.float_lit);
+            break;
+        case EXPR_CHAR_LIT:
+            node->resolved_type = resolve_char_lit(&node->inner.char_lit);
+            break;
+        case EXPR_STR_LIT:
+            node->resolved_type = resolve_str_lit(&node->inner.str_lit);
+            break;
+        case EXPR_VAR_REF:
+            node->resolved_type = resolve_var_ref(&node->inner.var_ref);
+            break;
+        case EXPR_ASSIGN:
+            node->resolved_type = resolve_assign(&node->inner.assign);
+            break;
+        case EXPR_CALL:
+            node->resolved_type = resolve_call(&node->inner.call);
+            break;
+        case EXPR_UNARY:
+            node->resolved_type = resolve_unary(&node->inner.unary);
+            break;
+        case EXPR_BINARY:
+            node->resolved_type = resolve_binary(&node->inner.binary);
+            break;
+    }
+}
+
+static void type_check_return(struct return_node* node) {
+    if (node->ret_val != NULL) type_check_expr(node->ret_val);
+}
+
+static void type_check_if(struct if_node* node) {
+    printf("tc if\n");
+    type_check_expr(node->cond);
+    type_check_stmt(node->true_branch);
+    if (node->false_branch != NULL) type_check_stmt(node->false_branch);
+}
 
 static void type_check_stmt(struct stmt_node* node) {
     switch (node->type) {
@@ -59,7 +255,16 @@ static void type_check_group(struct group_node* node) {
 static void type_check_fn_decl(struct fn_decl_node* node) {
     if (node->scope->next_out != scope) TYPE_PANIC("scopes are borked");
     scope = node->scope;
+
+    node->return_type.def_ref = resolve_type_ref(&node->return_type);
+
+    for (struct args_decl_node* arg_decl = node->args;
+            arg_decl != NULL;
+            arg_decl = arg_decl->next)
+        type_check_var_decl(arg_decl->decl);
+
     type_check_group(&node->body);
+
     scope = scope->next_out;
 }