basic printers, type printers, some fixes, part of expression printers

include/basic_printers.hpp

@@ -0,0 +1,52 @@
+#pragma once
+
+#include "basic_nodes.hpp"
+#include <iostream>
+
+namespace printers {
+
+class Printer {
+public:
+  Printer(std::ostream &output, size_t tab_width,
+          bool print_words_instead_of_symbols)
+      : output_(output), tab_width_(tab_width),
+        print_words_instead_of_symbols_(print_words_instead_of_symbols),
+        current_column_(0) {}
+
+  template <typename T> void print(const T &value) { output_ << value; }
+
+  void new_line() {
+    print('\n');
+    print_spaces(current_column_ * tab_width_);
+  }
+
+  void indent() { ++current_column_; }
+
+  void deindent() { --current_column_; }
+
+  void tab() { print_spaces(tab_width_); }
+
+  void space() { print_spaces(1); }
+
+  bool print_words_instead_of_symbols() {
+    return print_words_instead_of_symbols_;
+  }
+
+private:
+  void print_spaces(size_t n) { print(std::string(n, ' ')); }
+
+private:
+  std::ostream &output_;
+  size_t tab_width_ = 2;
+  bool print_words_instead_of_symbols_ = false;
+
+  size_t current_column_ = 0;
+};
+
+void print_literal(const nodes::Literal &literal, Printer &printer);
+
+void print_identifier(const nodes::Identifier &identifier, Printer &printer);
+
+void print_annotation(const std::string &annotation, Printer &printer);
+
+} // namespace printers