1 files changed, 46 insertions, 0 deletions
diff --git a/21sh/ll-expr/src/parser/parser.h b/21sh/ll-expr/src/parser/parser.h
new file mode 100644
index 0000000..057c6bc
--- /dev/null
+++ b/21sh/ll-expr/src/parser/parser.h
@@ -0,0 +1,46 @@
+#ifndef PARSER_H
+#define PARSER_H
+
+#include "ast.h"
+#include "lexer.h"
+
+enum parser_status
+{
+    PARSER_OK,
+    PARSER_UNEXPECTED_TOKEN,
+};
+
+/**
+ * \brief Parses an expression or nothing.
+ *
+ * input =     EOF
+ *          |  exp EOF ;
+ */
+struct ast *parse(enum parser_status *status, struct lexer *lexer);
+
+/**
+ * \brief Parses sexp expressions separated by + and -.
+ *
+ * exp =       sexp  { ( '+' | '-' ) sexp } ;
+ */
+struct ast *parse_exp(enum parser_status *status, struct lexer *lexer);
+
+/**
+ * \brief Parses texp expressions separated by * and /.
+ *
+ * sexp =      texp  { ('*' | '/' ) texp } ;
+ */
+struct ast *parse_sexp(enum parser_status *status, struct lexer *lexer);
+
+/**
+ * \brief Parses a number, a - a number, or a parenthesized expression.
+ *
+ * texp =      NUMBER
+ *          |  '-' NUMBER
+ *          |  '-' '(' exp ')'
+ *          |  '(' exp ')'
+ *          ;
+ */
+struct ast *parse_texp(enum parser_status *status, struct lexer *lexer);
+
+#endif /* !PARSER_H */