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//! This module contains free-standing functions for creating AST fragments out
//! of smaller pieces.
use itertools::Itertools;
use crate::{ast, AstNode, SourceFile};
pub fn name_ref(text: &str) -> ast::NameRef {
ast_from_text(&format!("fn f() {{ {}; }}", text))
}
pub fn path_from_name_ref(name_ref: ast::NameRef) -> ast::Path {
path_from_text(&name_ref.syntax().to_string())
}
pub fn path_qualified(qual: ast::Path, name_ref: ast::NameRef) -> ast::Path {
path_from_text(&format!("{}::{}", qual.syntax(), name_ref.syntax()))
}
fn path_from_text(text: &str) -> ast::Path {
ast_from_text(text)
}
pub fn record_field(name: ast::NameRef, expr: Option<ast::Expr>) -> ast::RecordField {
return match expr {
Some(expr) => from_text(&format!("{}: {}", name.syntax(), expr.syntax())),
None => from_text(&name.syntax().to_string()),
};
fn from_text(text: &str) -> ast::RecordField {
ast_from_text(&format!("fn f() {{ S {{ {}, }} }}", text))
}
}
pub fn block_from_expr(e: ast::Expr) -> ast::Block {
return from_text(&format!("{{ {} }}", e.syntax()));
fn from_text(text: &str) -> ast::Block {
ast_from_text(&format!("fn f() {}", text))
}
}
pub fn expr_unit() -> ast::Expr {
expr_from_text("()")
}
pub fn expr_unimplemented() -> ast::Expr {
expr_from_text("unimplemented!()")
}
fn expr_from_text(text: &str) -> ast::Expr {
ast_from_text(&format!("const C: () = {};", text))
}
pub fn bind_pat(name: ast::Name) -> ast::BindPat {
return from_text(name.text());
fn from_text(text: &str) -> ast::BindPat {
ast_from_text(&format!("fn f({}: ())", text))
}
}
pub fn placeholder_pat() -> ast::PlaceholderPat {
return from_text("_");
fn from_text(text: &str) -> ast::PlaceholderPat {
ast_from_text(&format!("fn f({}: ())", text))
}
}
pub fn tuple_struct_pat(
path: ast::Path,
pats: impl Iterator<Item = ast::Pat>,
) -> ast::TupleStructPat {
let pats_str = pats.map(|p| p.syntax().to_string()).join(", ");
return from_text(&format!("{}({})", path.syntax(), pats_str));
fn from_text(text: &str) -> ast::TupleStructPat {
ast_from_text(&format!("fn f({}: ())", text))
}
}
pub fn record_pat(path: ast::Path, pats: impl Iterator<Item = ast::Pat>) -> ast::RecordPat {
let pats_str = pats.map(|p| p.syntax().to_string()).join(", ");
return from_text(&format!("{}{{ {} }}", path.syntax(), pats_str));
fn from_text(text: &str) -> ast::RecordPat {
ast_from_text(&format!("fn f({}: ())", text))
}
}
pub fn path_pat(path: ast::Path) -> ast::PathPat {
let path_str = path.syntax().text().to_string();
return from_text(path_str.as_str());
fn from_text(text: &str) -> ast::PathPat {
ast_from_text(&format!("fn f({}: ())", text))
}
}
pub fn match_arm(pats: impl Iterator<Item = ast::Pat>, expr: ast::Expr) -> ast::MatchArm {
let pats_str = pats.map(|p| p.syntax().to_string()).join(" | ");
return from_text(&format!("{} => {}", pats_str, expr.syntax()));
fn from_text(text: &str) -> ast::MatchArm {
ast_from_text(&format!("fn f() {{ match () {{{}}} }}", text))
}
}
pub fn match_arm_list(arms: impl Iterator<Item = ast::MatchArm>) -> ast::MatchArmList {
let arms_str = arms.map(|arm| format!("\n {}", arm.syntax())).join(",");
return from_text(&format!("{},\n", arms_str));
fn from_text(text: &str) -> ast::MatchArmList {
ast_from_text(&format!("fn f() {{ match () {{{}}} }}", text))
}
}
pub fn where_pred(path: ast::Path, bounds: impl Iterator<Item = ast::TypeBound>) -> ast::WherePred {
let bounds = bounds.map(|b| b.syntax().to_string()).join(" + ");
return from_text(&format!("{}: {}", path.syntax(), bounds));
fn from_text(text: &str) -> ast::WherePred {
ast_from_text(&format!("fn f() where {} {{ }}", text))
}
}
pub fn where_clause(preds: impl Iterator<Item = ast::WherePred>) -> ast::WhereClause {
let preds = preds.map(|p| p.syntax().to_string()).join(", ");
return from_text(preds.as_str());
fn from_text(text: &str) -> ast::WhereClause {
ast_from_text(&format!("fn f() where {} {{ }}", text))
}
}
fn ast_from_text<N: AstNode>(text: &str) -> N {
let parse = SourceFile::parse(text);
let res = parse.tree().syntax().descendants().find_map(N::cast).unwrap();
res
}
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