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use std::fmt::{self, Write};
use crate::block::Block;
use crate::body::Body;
use crate::bound::Bound;
use crate::docs::Docs;
use crate::field::Field;
use crate::formatter::Formatter;
use crate::formatter::{fmt_bounds, fmt_generics};
use crate::r#type::Type;
/// Defines a function.
#[derive(Debug, Clone)]
pub struct Function {
/// The name of the function.
name: String,
/// The function's documentation.
docs: Option<Docs>,
/// A lint attribute used to suppress a warning or error.
allow: Option<String>,
/// Function visibility.
vis: Option<String>,
/// Function generics.
generics: Vec<String>,
/// If the function takes `&self` or `&mut self`.
arg_self: Option<String>,
/// Function arguments.
args: Vec<Field>,
/// Return type.
ret: Option<Type>,
/// Where bounds.
bounds: Vec<Bound>,
/// Body contents.
pub body: Option<Vec<Body>>,
/// Function attributes, e.g., `#[no_mangle]`.
attributes: Vec<String>,
/// Function `extern` ABI.
extern_abi: Option<String>,
/// Whether or not this function is `async` or not.
r#async: bool,
}
impl Function {
/// Return a new function definition.
///
/// # Arguments
///
/// * `name` - The name of the function.
///
/// # Examples
///
/// ```
/// use rust_codegen::Function;
///
/// let foo_fn = Function::new("foo_fn");
/// ```
pub fn new(name: &str) -> Self {
Function {
name: name.to_string(),
docs: None,
allow: None,
vis: None,
generics: vec![],
arg_self: None,
args: vec![],
ret: None,
bounds: vec![],
body: Some(vec![]),
attributes: vec![],
extern_abi: None,
r#async: false,
}
}
/// Set the function documentation.
///
/// # Arguments
///
/// * `docs` - The docs to set for the function.
///
/// # Examples
///
/// ```
/// use rust_codegen::Function;
///
/// let mut foo_fn = Function::new("foo_fn");
/// foo_fn.doc("Sample Foo function documentation.");
/// ```
pub fn doc(&mut self, docs: &str) -> &mut Self {
self.docs = Some(Docs::new(docs));
self
}
/// Specify lint attribute to supress a warning or error.
///
/// # Arguments
///
/// * `allow` - The lint attribute to add.
///
/// # Examples
///
/// ```
/// use rust_codegen::Function;
///
/// let mut foo_fn = Function::new("foo_fn");
/// foo_fn.allow("dead_code");
/// ```
pub fn allow(&mut self, allow: &str) -> &mut Self {
self.allow = Some(allow.to_string());
self
}
/// Set the function visibility.
///
/// # Arguments
///
/// * `vis` - The visiblity to set for the function.
///
/// # Examples
///
/// ```
/// use rust_codegen::Function;
///
/// let mut foo_fn = Function::new("foo_fn");
/// foo_fn.vis("pub");
/// ```
pub fn vis(&mut self, vis: &str) -> &mut Self {
self.vis = Some(vis.to_string());
self
}
/// Set whether this function is async or not.
///
/// # Arguments
///
/// * `async` - Indicates whether this function is async or not.
///
/// # Examples
///
/// ```
/// use rust_codegen::Function;
///
/// let mut foo_fn = Function::new("foo_fn");
/// foo_fn.set_async(true);
/// ```
pub fn set_async(&mut self, r#async: bool) -> &mut Self {
self.r#async = r#async;
self
}
/// Add a generic to the function.
///
/// # Arguments
///
/// * `name` - The name of the generic to add.
///
/// # Examples
///
/// ```
/// use rust_codegen::Function;
///
/// let mut foo_fn = Function::new("foo_fn");
/// foo_fn.generic("T");
/// ```
pub fn generic(&mut self, name: &str) -> &mut Self {
self.generics.push(name.to_string());
self
}
/// Add `self` as a function argument.
///
/// # Examples
///
/// ```
/// use rust_codegen::Function;
///
/// let mut foo_fn = Function::new("foo_fn");
/// foo_fn.arg_self();
/// ```
pub fn arg_self(&mut self) -> &mut Self {
self.arg_self = Some("self".to_string());
self
}
/// Add `&self` as a function argument.
///
/// # Examples
///
/// ```
/// use rust_codegen::Function;
///
/// let mut foo_fn = Function::new("foo_fn");
/// foo_fn.arg_ref_self();
/// ```
pub fn arg_ref_self(&mut self) -> &mut Self {
self.arg_self = Some("&self".to_string());
self
}
/// Add `&mut self` as a function argument.
///
/// # Examples
///
/// ```
/// use rust_codegen::Function;
///
/// let mut foo_fn = Function::new("foo_fn");
/// foo_fn.arg_mut_self();
/// ```
pub fn arg_mut_self(&mut self) -> &mut Self {
self.arg_self = Some("&mut self".to_string());
self
}
/// Add a function argument.
///
/// # Arguments
///
/// * `name` - The name of the argument.
/// * `ty` - The type of the argument.
///
/// # Examples
///
/// ```
/// use rust_codegen::Function;
///
/// let mut foo_fn = Function::new("foo_fn");
/// foo_fn.arg("name", "&str");
/// ```
pub fn arg<T>(&mut self, name: &str, ty: T) -> &mut Self
where
T: Into<Type>,
{
self.args.push(Field {
name: name.to_string(),
ty: ty.into(),
// While a `Field` is used here, both `documentation`
// and `annotation` does not make sense for function arguments.
// Simply use empty strings.
documentation: Vec::new(),
annotation: Vec::new(),
});
self
}
/// Set the function return type.
///
/// # Arguments
///
/// * `ty` - The return type.
///
/// # Examples
///
/// ```
/// use rust_codegen::Function;
///
/// let mut foo_fn = Function::new("foo_fn");
/// foo_fn.ret("String");
/// ```
pub fn ret<T>(&mut self, ty: T) -> &mut Self
where
T: Into<Type>,
{
self.ret = Some(ty.into());
self
}
/// Add a `where` bound to the function.
///
/// # Arguments
///
/// * `name ` - The name of the bound.
/// * `ty` - The type of the bound.
///
/// # Examples
///
/// ```
/// use rust_codegen::Function;
///
/// let mut foo_fn = Function::new("foo_fn");
/// foo_fn.bound("A", "TraitA");
/// ```
pub fn bound<T>(&mut self, name: &str, ty: T) -> &mut Self
where
T: Into<Type>,
{
self.bounds.push(Bound {
name: name.to_string(),
bound: vec![ty.into()],
});
self
}
/// Push a line to the function implementation.
///
/// # Arguments
///
/// * `line` - The line to add to the function.
///
/// # Examples
///
/// ```
/// use rust_codegen::Function;
///
/// let mut foo_fn = Function::new("foo_fn");
/// foo_fn.line("println!(\"Hello, world!\")");
/// ```
pub fn line<T>(&mut self, line: T) -> &mut Self
where
T: ToString,
{
self.body
.get_or_insert(vec![])
.push(Body::String(line.to_string()));
self
}
/// Add an attribute to the function.
///
/// # Arguments
///
/// * `attribute` - The attribute to add.
///
/// # Examples
///
/// ```
/// use rust_codegen::Function;
///
/// let mut foo_fn = Function::new("foo_fn");
/// foo_fn.attr("test");
/// ```
pub fn attr(&mut self, attribute: &str) -> &mut Self {
self.attributes.push(attribute.to_string());
self
}
/// Specify an `extern` ABI for the function.
///
/// # Arguments
///
/// * `abi` - The extern ABI to add.
///
/// # Examples
///
/// ```
/// use rust_codegen::Function;
///
/// let mut foo_fn = Function::new("foo_fn");
/// foo_fn.extern_abi("C");
/// ```
pub fn extern_abi(&mut self, abi: &str) -> &mut Self {
self.extern_abi.replace(abi.to_string());
self
}
/// Push a block to the function implementation.
///
/// # Arguments
///
/// * `block` - The block to push to the function.
///
/// # Examples
///
/// ```
/// use rust_codegen::*;
///
/// let mut foo_fn = Function::new("foo_fn");
///
/// let mut block = Block::new("");
/// block.line("println!(\"Hello, world!\");");
///
/// foo_fn.push_block(block);
/// ```
pub fn push_block(&mut self, block: Block) -> &mut Self {
self.body.get_or_insert(vec![]).push(Body::Block(block));
self
}
/// Formats the function using the given formatter.
///
/// # Arguments
///
/// * `is_trait` - Indicates whether it is a trait or not.
/// * `fmt` - The formatter to use.
///
/// # Examples
///
/// ```
/// use rust_codegen::*;
///
/// let mut dest = String::new();
/// let mut fmt = Formatter::new(&mut dest);
///
/// let mut foo_fn = Function::new("foo_fn");
/// foo_fn.fmt(false, &mut fmt);
/// ```
pub fn fmt(&self, is_trait: bool, fmt: &mut Formatter<'_>) -> fmt::Result {
if let Some(ref docs) = self.docs {
docs.fmt(fmt)?;
}
if let Some(ref allow) = self.allow {
write!(fmt, "#[allow({})]\n", allow)?;
}
for attr in self.attributes.iter() {
write!(fmt, "#[{}]\n", attr)?;
}
if is_trait {
assert!(
self.vis.is_none(),
"trait fns do not have visibility modifiers"
);
}
if let Some(ref vis) = self.vis {
write!(fmt, "{} ", vis)?;
}
if let Some(ref extern_abi) = self.extern_abi {
write!(fmt, "extern \"{extern_abi}\" ", extern_abi = extern_abi)?;
}
if self.r#async {
write!(fmt, "async ")?;
}
write!(fmt, "fn {}", self.name)?;
fmt_generics(&self.generics, fmt)?;
write!(fmt, "(")?;
if let Some(ref s) = self.arg_self {
write!(fmt, "{}", s)?;
}
for (i, arg) in self.args.iter().enumerate() {
if i != 0 || self.arg_self.is_some() {
write!(fmt, ", ")?;
}
write!(fmt, "{}: ", arg.name)?;
arg.ty.fmt(fmt)?;
}
write!(fmt, ")")?;
if let Some(ref ret) = self.ret {
write!(fmt, " -> ")?;
ret.fmt(fmt)?;
}
fmt_bounds(&self.bounds, fmt)?;
match self.body {
Some(ref body) => fmt.block(|fmt| {
for b in body {
b.fmt(fmt)?;
}
Ok(())
}),
None => {
if !is_trait {
panic!("impl blocks must define fn bodies");
}
write!(fmt, ";\n")
}
}
}
}