From 7f03fe8cf0f8df53379252e6bf37bad1c1155d67 Mon Sep 17 00:00:00 2001
From: rexim <reximkut@gmail.com>
Date: Tue, 28 Aug 2018 18:57:33 +0700
Subject: [PATCH] (#303) Introduce string and stream readers

---
 src/script/parser.c | 21 ++++++++++++++++++---
 src/script/parser.h |  3 ++-
 2 files changed, 20 insertions(+), 4 deletions(-)

diff --git a/src/script/parser.c b/src/script/parser.c
index 9f063a42..88b3451e 100644
--- a/src/script/parser.c
+++ b/src/script/parser.c
@@ -1,16 +1,19 @@
 #include <assert.h>
-#include <stdlib.h>
 #include <ctype.h>
+#include <stdio.h>
+#include <stdlib.h>
 
 #include "script/parser.h"
 
+static struct ParseResult parse_expr(struct Token current_token);
+
 static struct ParseResult parse_cdr(struct Token current_token)
 {
     if (*current_token.begin != '.') {
         return parse_failure("Expected .", current_token.begin);
     }
 
-    struct ParseResult cdr = parse_expr(next_token(current_token.end));
+    struct ParseResult cdr = read_expr_from_string(current_token.end);
     if (cdr.is_error) {
         return cdr;
     }
@@ -131,7 +134,7 @@ static struct ParseResult parse_symbol(struct Token current_token)
         current_token.end);
 }
 
-struct ParseResult parse_expr(struct Token current_token)
+static struct ParseResult parse_expr(struct Token current_token)
 {
     if (*current_token.begin == 0) {
         return parse_failure("EOF", current_token.begin);
@@ -151,6 +154,18 @@ struct ParseResult parse_expr(struct Token current_token)
     return parse_symbol(current_token);
 }
 
+struct ParseResult read_expr_from_string(const char *str)
+{
+    assert(str);
+    return parse_expr(next_token(str));
+}
+
+struct ParseResult read_expr_from_stream(FILE *stream)
+{
+    assert(stream);
+    return parse_failure("not implemented", NULL);
+}
+
 struct ParseResult parse_success(struct Expr expr,
                                  const char *end)
 {
diff --git a/src/script/parser.h b/src/script/parser.h
index 01b0b672..5f04fc56 100644
--- a/src/script/parser.h
+++ b/src/script/parser.h
@@ -21,7 +21,8 @@ struct ParseResult parse_success(struct Expr expr,
 struct ParseResult parse_failure(const char *error,
                                  const char *end);
 
-struct ParseResult parse_expr(struct Token token);
+struct ParseResult read_expr_from_string(const char *str);
+struct ParseResult read_expr_from_stream(FILE *stream);
 
 void print_parse_error(FILE *stream,
                        const char *str,
-- 
2.44.0