use crate::algorithm::Printer;
use crate::iter::IterDelimited;
use crate::INDENT;
use std::ptr;
use syn::{
BoundLifetimes, ConstParam, GenericParam, Generics, LifetimeDef, PredicateEq,
PredicateLifetime, PredicateType, TraitBound, TraitBoundModifier, TypeParam, TypeParamBound,
WhereClause, WherePredicate,
};
impl Printer {
pub fn generics(&mut self, generics: &Generics) {
if generics.params.is_empty() {
return;
}
self.word("<");
self.cbox(0);
self.zerobreak();
#[derive(Ord, PartialOrd, Eq, PartialEq)]
enum Group {
First,
Second,
}
fn group(param: &GenericParam) -> Group {
match param {
GenericParam::Lifetime(_) => Group::First,
GenericParam::Type(_) | GenericParam::Const(_) => Group::Second,
}
}
let last = generics.params.iter().max_by_key(|param| group(param));
for current_group in [Group::First, Group::Second] {
for param in &generics.params {
if group(param) == current_group {
self.generic_param(param);
self.trailing_comma(ptr::eq(param, last.unwrap()));
}
}
}
self.offset(-INDENT);
self.end();
self.word(">");
}
fn generic_param(&mut self, generic_param: &GenericParam) {
match generic_param {
GenericParam::Type(type_param) => self.type_param(type_param),
GenericParam::Lifetime(lifetime_def) => self.lifetime_def(lifetime_def),
GenericParam::Const(const_param) => self.const_param(const_param),
}
}
pub fn bound_lifetimes(&mut self, bound_lifetimes: &BoundLifetimes) {
self.word("for<");
for lifetime_def in bound_lifetimes.lifetimes.iter().delimited() {
self.lifetime_def(&lifetime_def);
if !lifetime_def.is_last {
self.word(", ");
}
}
self.word("> ");
}
fn lifetime_def(&mut self, lifetime_def: &LifetimeDef) {
self.outer_attrs(&lifetime_def.attrs);
self.lifetime(&lifetime_def.lifetime);
for lifetime in lifetime_def.bounds.iter().delimited() {
if lifetime.is_first {
self.word(": ");
} else {
self.word(" + ");
}
self.lifetime(&lifetime);
}
}
fn type_param(&mut self, type_param: &TypeParam) {
self.outer_attrs(&type_param.attrs);
self.ident(&type_param.ident);
self.ibox(INDENT);
for type_param_bound in type_param.bounds.iter().delimited() {
if type_param_bound.is_first {
self.word(": ");
} else {
self.space();
self.word("+ ");
}
self.type_param_bound(&type_param_bound);
}
if let Some(default) = &type_param.default {
self.space();
self.word("= ");
self.ty(default);
}
self.end();
}
pub fn type_param_bound(&mut self, type_param_bound: &TypeParamBound) {
match type_param_bound {
TypeParamBound::Trait(trait_bound) => self.trait_bound(trait_bound),
TypeParamBound::Lifetime(lifetime) => self.lifetime(lifetime),
}
}
fn trait_bound(&mut self, trait_bound: &TraitBound) {
if trait_bound.paren_token.is_some() {
self.word("(");
}
let skip = match trait_bound.path.segments.first() {
Some(segment) if segment.ident == "const" => {
self.word("~const ");
1
}
_ => 0,
};
self.trait_bound_modifier(&trait_bound.modifier);
if let Some(bound_lifetimes) = &trait_bound.lifetimes {
self.bound_lifetimes(bound_lifetimes);
}
for segment in trait_bound.path.segments.iter().skip(skip).delimited() {
if !segment.is_first || trait_bound.path.leading_colon.is_some() {
self.word("::");
}
self.path_segment(&segment);
}
if trait_bound.paren_token.is_some() {
self.word(")");
}
}
fn trait_bound_modifier(&mut self, trait_bound_modifier: &TraitBoundModifier) {
match trait_bound_modifier {
TraitBoundModifier::None => {}
TraitBoundModifier::Maybe(_question_mark) => self.word("?"),
}
}
fn const_param(&mut self, const_param: &ConstParam) {
self.outer_attrs(&const_param.attrs);
self.word("const ");
self.ident(&const_param.ident);
self.word(": ");
self.ty(&const_param.ty);
if let Some(default) = &const_param.default {
self.word(" = ");
self.expr(default);
}
}
pub fn where_clause_for_body(&mut self, where_clause: &Option<WhereClause>) {
let hardbreaks = true;
let semi = false;
self.where_clause_impl(where_clause, hardbreaks, semi);
}
pub fn where_clause_semi(&mut self, where_clause: &Option<WhereClause>) {
let hardbreaks = true;
let semi = true;
self.where_clause_impl(where_clause, hardbreaks, semi);
}
pub fn where_clause_oneline(&mut self, where_clause: &Option<WhereClause>) {
let hardbreaks = false;
let semi = false;
self.where_clause_impl(where_clause, hardbreaks, semi);
}
pub fn where_clause_oneline_semi(&mut self, where_clause: &Option<WhereClause>) {
let hardbreaks = false;
let semi = true;
self.where_clause_impl(where_clause, hardbreaks, semi);
}
fn where_clause_impl(
&mut self,
where_clause: &Option<WhereClause>,
hardbreaks: bool,
semi: bool,
) {
let where_clause = match where_clause {
Some(where_clause) if !where_clause.predicates.is_empty() => where_clause,
_ => {
if semi {
self.word(";");
} else {
self.nbsp();
}
return;
}
};
if hardbreaks {
self.hardbreak();
self.offset(-INDENT);
self.word("where");
self.hardbreak();
for predicate in where_clause.predicates.iter().delimited() {
self.where_predicate(&predicate);
if predicate.is_last && semi {
self.word(";");
} else {
self.word(",");
self.hardbreak();
}
}
if !semi {
self.offset(-INDENT);
}
} else {
self.space();
self.offset(-INDENT);
self.word("where");
self.space();
for predicate in where_clause.predicates.iter().delimited() {
self.where_predicate(&predicate);
if predicate.is_last && semi {
self.word(";");
} else {
self.trailing_comma_or_space(predicate.is_last);
}
}
if !semi {
self.offset(-INDENT);
}
}
}
fn where_predicate(&mut self, predicate: &WherePredicate) {
match predicate {
WherePredicate::Type(predicate) => self.predicate_type(predicate),
WherePredicate::Lifetime(predicate) => self.predicate_lifetime(predicate),
WherePredicate::Eq(predicate) => self.predicate_eq(predicate),
}
}
fn predicate_type(&mut self, predicate: &PredicateType) {
if let Some(bound_lifetimes) = &predicate.lifetimes {
self.bound_lifetimes(bound_lifetimes);
}
self.ty(&predicate.bounded_ty);
self.word(":");
if predicate.bounds.len() == 1 {
self.ibox(0);
} else {
self.ibox(INDENT);
}
for type_param_bound in predicate.bounds.iter().delimited() {
if type_param_bound.is_first {
self.nbsp();
} else {
self.space();
self.word("+ ");
}
self.type_param_bound(&type_param_bound);
}
self.end();
}
fn predicate_lifetime(&mut self, predicate: &PredicateLifetime) {
self.lifetime(&predicate.lifetime);
self.word(":");
self.ibox(INDENT);
for lifetime in predicate.bounds.iter().delimited() {
if lifetime.is_first {
self.nbsp();
} else {
self.space();
self.word("+ ");
}
self.lifetime(&lifetime);
}
self.end();
}
fn predicate_eq(&mut self, predicate: &PredicateEq) {
self.ty(&predicate.lhs_ty);
self.word(" = ");
self.ty(&predicate.rhs_ty);
}
}