1 files changed, 42 insertions, 0 deletions
diff --git a/server/lexer/input.hpp b/server/lexer/input.hpp
new file mode 100644
index 0000000..1104a4b
--- /dev/null
+++ b/server/lexer/input.hpp
@@ -0,0 +1,42 @@
+#pragma once
+
+#include "error.hpp"
+
+#include <cstddef>
+
+#include <string_view>
+
+namespace math::server::lexer {
+
+class Input {
+public:
+    explicit Input(const std::string_view& input)
+        : m_pos{0}, m_input{input}
+    { }
+
+    const std::string_view& get_input() const { return m_input; }
+
+    std::size_t get_pos() const { return m_pos; }
+
+    std::size_t get_length() const { return m_input.length(); }
+
+    bool empty() const { return m_input.empty(); }
+
+    void consume(std::size_t len) {
+        if (m_input.length() < len) {
+            throw LexerError{"internal: not enough input to consume"};
+        }
+        m_pos += len;
+        m_input.remove_prefix(len);
+    }
+
+    void consume(const std::string_view& sub) {
+        consume(sub.length());
+    }
+
+private:
+    std::size_t m_pos;
+    std::string_view m_input;
+};
+
+}