From 453a8ab0da0b9b29e95d8efc638bb25aca61a64d Mon Sep 17 00:00:00 2001
From: Matteo Flebus <matteo.flebus@epita.fr>
Date: Thu, 8 Jan 2026 16:32:48 +0100
Subject: [PATCH] feat(lexer): usefull functions

---
 src/lexer/lexer.c | 67 +++++++++++++++++++++++++++++++++++++++++++++++
 src/lexer/lexer.h | 36 +++++++++++++++++++++++++
 2 files changed, 103 insertions(+)

diff --git a/src/lexer/lexer.c b/src/lexer/lexer.c
index e69de29..5b03c18 100644
--- a/src/lexer/lexer.c
+++ b/src/lexer/lexer.c
@@ -0,0 +1,67 @@
+#include "lexer.h"
+
+#include <stdbool.h>
+
+#include "io_backend/io_backend.h"
+
+static char *end_last_token;
+static ssize_t remaining_chars;
+
+char *new_token(char *begin, size_t size)
+{
+    char *res = calloc(size + 1, sizeof(char));
+    if (res == NULL)
+        return NULL;
+    strncpy(res, begin, size);
+    return res;
+}
+
+char *stream_init(void)
+{
+    char *stream;
+
+    if (remaining_chars == 0)
+    {
+        remaining_chars = stream_read(&stream);
+    }
+    else
+    {
+        stream = end_last_token;
+    }
+
+    return stream;
+}
+
+char *get_token(void)
+{
+    char *stream = stream_init();
+
+    bool inquotes = false;
+    ssize_t i = 0;
+
+    while (i < remaining_chars)
+    {
+        switch (stream[i])
+        {
+        case '\'':
+            inquotes = !inquotes;
+            break;
+
+        case ' ' | '\n' | '\t':
+            if (inquotes)
+                break;
+            else
+            {
+                // token creation
+                // skip blank char
+                // exit from loop
+                char *token = new_token(stream, i);
+            }
+        default:
+            break;
+        }
+        i++;
+    }
+
+    remaining_chars -= i;
+}
diff --git a/src/lexer/lexer.h b/src/lexer/lexer.h
index e69de29..d9a484c 100644
--- a/src/lexer/lexer.h
+++ b/src/lexer/lexer.h
@@ -0,0 +1,36 @@
+#ifndef LEXER_H
+#define LEXER_H
+
+/* @return: char*, the next token
+ *
+ */
+char *get_token(void);
+
+/*
+ * @warning: NOT IMPLEMENTED.
+ *
+ * @note: maybe usefull for subshells.
+ */
+
+char *get_token_str(void);
+
+/*
+ * @brief: return a newly allocated token.
+ *         This token contains [size] chars, starting from [begin].
+ *
+ * @return: NULL on error, null-terminated char* otherwise.
+ *
+ */
+char *new_token(char *begin, ssize_t size);
+
+/*
+ * @brief: checks if the stream used for the last token creation is empty.
+ *         If it is, it calls stream_read() from IO_backend,
+ *         and sets [remaing_chars].
+ *         If not, it starts from the end of the last token.
+ *
+ * @return: char* stream from which we tokenise.
+ */
+char *stream_init(void);
+
+#endif /* LEXER_H */