Generator

Overview

Utility for writing generated code to files with automatic indentation, separators, and compile-time warning emission.

Why Use This?

Code generators need consistent formatting and diagnostic integration. generator provides a simple builder for structured text output without manual indent tracking or file management.

Types

Type	Description
generator	Indented output writer targeting a file

Functions

generator(output_file)

Construct and open output file for writing. Truncates existing content.

Signature: generator(const std::string& output_file)

Parameters:

• output_file — path to the output file

out

Emit a line with current indentation.

Signature: generator& out(const std::string& data)

Parameters:

• data — line content (newline appended automatically)

Returns: *this for chaining

indent

Increase indentation level by one (2 spaces per level).

Signature: generator& indent()

Returns: *this for chaining

unindent

Decrease indentation level by one.

Signature: generator& unindent()

Returns: *this for chaining

separator

Emit a // followed by 77 dashes.

Signature: generator& separator()

Returns: *this for chaining

named_separator

Emit a // === name === separator line.

Signature: generator& named_separator(const std::string& name)

Parameters:

• name — label for the separator

Returns: *this for chaining

warn

Add a compile-time warning to the generated output.

Signatures:

• generator& warn(const std::string& message, source_location loc = {})
• generator& warn(const std::string& message, const node_ptr node)

Parameters:

• message — warning text
• loc — optional source location for file:line context
• node — node whose location to use

Returns: *this for chaining

Notes: Generates #pragma message (MSVC) or #warning (GCC/Clang) directives. Warnings appear when the generated file is compiled.

done

Finalize and close the output file. Writes accumulated warnings.

Signature: bool done()

Returns: true on success, false on file write failure

Notes: Also called by the destructor, but prefer explicit done() to check the return value.

Example:

xccmeta::generator gen("output.generated.hpp");

gen.out("#pragma once");
gen.out("#include <string>");
gen.out("");

for (auto& type : types) {
  gen.named_separator(type->get_name());
  gen.out("struct " + type->get_name() + "_Meta {");
  gen.indent();
  gen.out("static constexpr const char* name = \"" + type->get_name() + "\";");
  gen.unindent();
  gen.out("};");
  gen.out("");
}

if (!gen.done()) {
  std::cerr << "Failed to write output\n";
}