From 52ac67026f66417502c2dc70e2cc1252e106054b Mon Sep 17 00:00:00 2001
From: Danila Fedorin <danila.fedorin@gmail.com>
Date: Sun, 25 Feb 2018 14:06:15 -0800
Subject: [PATCH] Remove function tokens. If functions are first class, they're
 variables.

---
 include/lexer.h |  1 -
 src/libabacus.c |  4 ----
 src/parser.c    | 51 +++++++++++++++++++++++++++++--------------------
 3 files changed, 30 insertions(+), 26 deletions(-)

diff --git a/include/lexer.h b/include/lexer.h
index 3df5bab..0ebc1b1 100644
--- a/include/lexer.h
+++ b/include/lexer.h
@@ -58,7 +58,6 @@ enum libab_lexer_token_e {
     TOKEN_OP_INFIX,
     TOKEN_OP_PREFIX,
     TOKEN_OP_POSTFIX,
-    TOKEN_FUN,
     TOKEN_KW_IF,
     TOKEN_KW_ELSE,
     TOKEN_LAST
diff --git a/src/libabacus.c b/src/libabacus.c
index 5780095..3c64e91 100644
--- a/src/libabacus.c
+++ b/src/libabacus.c
@@ -69,10 +69,6 @@ libab_result libab_register_function(libab* ab, const char* name, libab_function
         result = LIBAB_MALLOC;
     }
 
-    if(result == LIBAB_SUCCESS) {
-        result = libab_convert_lex_result(eval_config_add(&ab->lexer.config, name, TOKEN_FUN));
-    }
-
     if(result == LIBAB_SUCCESS) {
         result = libab_table_put(&ab->table, name, new_entry);
     }
diff --git a/src/parser.c b/src/parser.c
index b8d4d39..58f33b9 100644
--- a/src/parser.c
+++ b/src/parser.c
@@ -223,8 +223,8 @@ libab_result _parse_call(struct parser_state* state, libab_tree** store_into) {
     libab_result result =  LIBAB_SUCCESS;
     libab_tree* temp;
 
-    if(_parser_is_type(state, TOKEN_FUN)) {
-        result = _parser_construct_node_both(state, state->current_match, store_into);
+    if(_parser_is_char(state, '(')) {
+        result = _parser_construct_node_vec(state->current_match, store_into);
         if(result == LIBAB_SUCCESS) {
             (*store_into)->variant = CALL;
         }
@@ -233,10 +233,6 @@ libab_result _parse_call(struct parser_state* state, libab_tree** store_into) {
         result = LIBAB_UNEXPECTED;
     }
 
-    if(result == LIBAB_SUCCESS) {
-        result = _parser_consume_char(state, '(');
-    }
-
     while(result == LIBAB_SUCCESS && !_parser_eof(state) && !_parser_is_char(state, ')')) {
         result = _parse_expression(state, &temp);
         if(result == LIBAB_SUCCESS) {
@@ -264,6 +260,19 @@ libab_result _parse_call(struct parser_state* state, libab_tree** store_into) {
     return result;
 }
 
+libab_result _parser_append_call(struct parser_state* state, ll* append_to) {
+    libab_result result;
+    libab_tree* into;
+    result = _parse_call(state, &into);
+    if(result == LIBAB_SUCCESS) {
+        result = libab_convert_ds_result(ll_append(append_to, into));
+        if(result != LIBAB_SUCCESS) {
+            libab_tree_free_recursive(into);
+        }
+    }
+    return result;
+}
+
 libab_result _parse_atom(struct parser_state* state, libab_tree** store_into) {
     libab_result result;
     if(_parser_is_type(state, TOKEN_NUM) || _parser_is_type(state, TOKEN_ID)) {
@@ -276,8 +285,6 @@ libab_result _parse_atom(struct parser_state* state, libab_tree** store_into) {
         result = _parse_if(state, store_into);
     } else if(_parser_is_char(state, '{')) {
         result = _parse_block(state, store_into, 1);
-    } else if(_parser_is_type(state, TOKEN_FUN)) {
-        result = _parse_call(state, store_into);
     } else {
         result = LIBAB_UNEXPECTED;
     }
@@ -371,7 +378,9 @@ libab_operator* _parser_find_operator(struct parser_state* state, libab_lexer_ma
 libab_result _parser_expression_tree(struct parser_state* state, ll* source, libab_tree** into) {
     libab_result result = LIBAB_SUCCESS;
     libab_tree* top = ll_poptail(source);
-    if(top && top->variant == OP) {
+    if(top == NULL) {
+        result = LIBAB_UNEXPECTED;
+    } else if(top->variant == OP) {
         libab_tree* left = NULL;
         libab_tree* right = NULL;
 
@@ -380,10 +389,6 @@ libab_result _parser_expression_tree(struct parser_state* state, ll* source, lib
             result = _parser_expression_tree(state, source, &left);
         }
 
-        if(result == LIBAB_SUCCESS && (left == NULL || right == NULL)) {
-            result = LIBAB_UNEXPECTED;
-        }
-
         if(result == LIBAB_SUCCESS) {
             result = libab_convert_ds_result(vec_add(&top->children, left));
         }
@@ -398,23 +403,23 @@ libab_result _parser_expression_tree(struct parser_state* state, ll* source, lib
             free(top);
             top = NULL;
         }
-    } else if(top && top->variant == UNARY_OP) {
+    } else if(top->variant == UNARY_OP || top->variant == CALL) {
         libab_tree* child = NULL;
 
         result = _parser_expression_tree(state, source, &child);
 
-        if(result == LIBAB_SUCCESS && child == NULL) {
-            result = LIBAB_UNEXPECTED;
-        }
-
         if(result == LIBAB_SUCCESS) {
             result = libab_convert_ds_result(vec_add(&top->children, child));
         }
 
         if(result != LIBAB_SUCCESS) {
             if(child) libab_tree_free_recursive(child);
-            libab_tree_free(top);
-            free(top);
+            if(top->variant == UNARY_OP) {
+                libab_tree_free(top);
+                free(top);
+            } else {
+                libab_tree_free_recursive(top);
+            }
             top = NULL;
         }
     }
@@ -438,7 +443,11 @@ libab_result _parse_expression(struct parser_state* state, libab_tree** store_in
         libab_lexer_match* new_token = state->current_match;
         char current_char = state->string[new_token->from];
         if(_parser_is_type(state, TOKEN_CHAR) && current_char != '{') {
-            if(current_char == '(') {
+            if(current_char == '(' && _parser_can_postfix_follow(last_type)) {
+                result = _parser_append_call(state, &out_stack);
+                if(result != LIBAB_SUCCESS) break;
+                new_type = EXPR_OP_POSTFIX;
+            } else if(current_char == '(') {
                 result = libab_convert_ds_result(ll_append(&op_stack, new_token));
                 if(result != LIBAB_SUCCESS) break;
                 _parser_state_step(state);