Module pw_format::macros

The macro module provides helpers that simplify writing proc macros that take format strings and arguments. This is accomplish with three main constructs:

• FormatAndArgsFlavor: A struct that implements syn::parse::Parse to parse a format string and its following arguments.
• FormatMacroGenerator: A trait used to implement the macro specific logic to generate code.
• generate: A function to handle the execution of the proc macro by calling into a FormatMacroGenerator.

Additionally PrintfFormatMacroGenerator trait and generate_printf function are provided to help when implementing generators that need to produce printf style format strings as part of their code generation.

Example

An example of implementing a proc macro is provided in the pw_format_example_macro crate

Structs

• CoreFmtFormatStringParser
  An implementation of FormatStringParser that parsers core::fmt style format strings.
• Error
  An error occurring during proc macro evaluation.
• FormatAndArgs
  A parsed format string and it’s arguments.
• FormatAndArgsFlavor
  A variant of FormatAndArgs that is generic over format string flavor.
• FormatParams
  Formatting parameters passed to an untyped conversion.
• PrintfFormatStringParser
  An implementation of FormatStringParser that parsers printf style format strings.

Enums

• Arg
  An argument to a pw_format backed macro.
• PrintfFormatStringFragment
  A fragment of a printf format string.

Traits

• CoreFmtFormatMacroGenerator
  A specialized generator for proc macros that produce core::fmt style format strings.
• FormatMacroGenerator
  A code generator for implementing a pw_format style macro.
• FormatStringParser
  A trait for parsing a string into a FormatString.
• PrintfFormatMacroGenerator
  A specialized generator for proc macros that produce printf style format strings.

Functions

• generate
  Generate code for a pw_format style proc macro.
• generate_core_fmt
  Generate code for a pw_format style proc macro that needs a core::fmt format string.
• generate_printf
  Generate code for a pw_format style proc macro that needs a printf format string.

Type Aliases

• Result
  An alias for a Result with an Error