Trait pw_format::macros::FormatMacroGenerator

pub trait FormatMacroGenerator {
    // Required methods
    fn finalize(self) -> Result<TokenStream>;
    fn string_fragment(&mut self, string: &str) -> Result<()>;
    fn integer_conversion(
        &mut self,
        params: &FormatParams,
        signed: bool,
        type_width: u8,
        expression: Arg
    ) -> Result<()>;
    fn string_conversion(&mut self, expression: Arg) -> Result<()>;
    fn char_conversion(&mut self, expression: Arg) -> Result<()>;

    // Provided method
    fn untyped_conversion(
        &mut self,
        _expression: Arg,
        _params: &FormatParams
    ) -> Result<()> { ... }
}

A code generator for implementing a pw_format style macro.

This trait serves as the primary interface between pw_format and a proc macro using it to implement format string and argument parsing. When evaluating the proc macro and generating code, generate will make repeated calls to string_fragment and the conversion functions. These calls will be made in the order they appear in the format string. After all fragments and conversions are processed, generate will call finalize.

For an example of implementing a FormatMacroGenerator see the pw_format_example_macro crate.

Required Methods

fn finalize(self) -> Result<TokenStream>

Called by generate at the end of code generation.

Consumes self and returns the code to be emitted by the proc macro of and Error.

fn string_fragment(&mut self, string: &str) -> Result<()>

Process a string fragment.

A string fragment is a string of characters that appear in a format string. This is different than a string_conversion which is a string provided through a conversion specifier (i.e. "%s").

fn integer_conversion( &mut self, params: &FormatParams, signed: bool, type_width: u8, expression: Arg ) -> Result<()>

Process an integer conversion.

fn string_conversion(&mut self, expression: Arg) -> Result<()>

Process a string conversion.

See string_fragment for a disambiguation between that function and this one.

fn char_conversion(&mut self, expression: Arg) -> Result<()>

Process a character conversion.

Provided Methods

fn untyped_conversion( &mut self, _expression: Arg, _params: &FormatParams ) -> Result<()>

Process an untyped conversion.

Implementors