1 files changed, 48 insertions, 0 deletions
diff --git a/42sh/src/lexer/lexer.h b/42sh/src/lexer/lexer.h
new file mode 100644
index 0000000..8d8cdf5
--- /dev/null
+++ b/42sh/src/lexer/lexer.h
@@ -0,0 +1,48 @@
+#ifndef LEXER_H
+#define LEXER_H
+
+#include <lexer/token.h>
+#include <stddef.h>
+#include <utils/libstring.h>
+
+// True if C could be used as a word
+#define ISWORD(C)                                                              \
+    C == TOKEN_WORD || C == TOKEN_THEN || C == TOKEN_ELIF || C == TOKEN_ELSE   \
+        || C == TOKEN_IF || C == TOKEN_WHILE || C == TOKEN_UNTIL               \
+        || C == TOKEN_DO || C == TOKEN_DONE || C == TOKEN_FOR || C == TOKEN_IN \
+        || C == TOKEN_NEG || C == TOKEN_FI || C == TOKEN_CURLY_LEFT            \
+        || C == TOKEN_CURLY_RIGHT
+
+struct lexer
+{
+    struct string *input; // input data
+    size_t pos; // the current offset inside the input data
+    char processed;
+    struct token current_tok; // next (if processed) token
+};
+
+// Creates a new lexer given an input string
+struct lexer *lexer_new(struct string *input);
+
+// Frees the given lexer, not its input
+void lexer_free(struct lexer *lexer);
+
+// Returns a token from the input string
+// If the token is a WORD, copies the word to the current_tok.value field
+struct token lexer_next_token(struct lexer *lexer);
+
+/*
+** Processes the next token if necessary
+** (previous call to lexer_pop or first call)
+*/
+// Returns the next token
+struct token lexer_peek(struct lexer *lexer);
+
+/*
+** Processes the next token if necessary
+** (previous call to lexer_pop or first call)
+*/
+// Returns the next token and moves the cursor forward
+struct token lexer_pop(struct lexer *lexer);
+
+#endif /* ! LEXER_H */