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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, SyntaxKind, SyntaxNode, SyntaxToken};
pub fn name(text: &str) -> ast::Name {
ast_from_text(&format!("mod {};", text))
}
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!()")
}
pub fn expr_path(path: ast::Path) -> ast::Expr {
expr_from_text(&path.syntax().to_string())
}
pub fn expr_continue() -> ast::Expr {
expr_from_text("continue")
}
pub fn expr_break() -> ast::Expr {
expr_from_text("break")
}
pub fn expr_return() -> ast::Expr {
expr_from_text("return")
}
pub fn expr_match(expr: ast::Expr, match_arm_list: ast::MatchArmList) -> ast::Expr {
expr_from_text(&format!("match {} {}", expr.syntax(), match_arm_list.syntax()))
}
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 IntoIterator<Item = ast::Pat>,
) -> ast::TupleStructPat {
let pats_str = pats.into_iter().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 IntoIterator<Item = ast::Pat>) -> ast::RecordPat {
let pats_str = pats.into_iter().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))
}
}
/// Returns a `BindPat` if the path has just one segment, a `PathPat` otherwise.
pub fn path_pat(path: ast::Path) -> ast::Pat {
let path_str = path.syntax().text().to_string();
return from_text(path_str.as_str());
fn from_text(text: &str) -> ast::Pat {
ast_from_text(&format!("fn f({}: ())", text))
}
}
pub fn match_arm(pats: impl IntoIterator<Item = ast::Pat>, expr: ast::Expr) -> ast::MatchArm {
let pats_str = pats.into_iter().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 IntoIterator<Item = ast::MatchArm>) -> ast::MatchArmList {
let arms_str = arms
.into_iter()
.map(|arm| {
let needs_comma = arm.expr().map_or(true, |it| !it.is_block_like());
let comma = if needs_comma { "," } else { "" };
format!(" {}{}\n", arm.syntax(), comma)
})
.collect::<String>();
return from_text(&format!("{}", arms_str));
fn from_text(text: &str) -> ast::MatchArmList {
ast_from_text(&format!("fn f() {{ match () {{\n{}}} }}", text))
}
}
pub fn where_pred(
path: ast::Path,
bounds: impl IntoIterator<Item = ast::TypeBound>,
) -> ast::WherePred {
let bounds = bounds.into_iter().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 IntoIterator<Item = ast::WherePred>) -> ast::WhereClause {
let preds = preds.into_iter().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))
}
}
pub fn if_expression(condition: &ast::Expr, statement: &str) -> ast::IfExpr {
ast_from_text(&format!(
"fn f() {{ if !{} {{\n {}\n}}\n}}",
condition.syntax().text(),
statement
))
}
pub fn let_stmt(pattern: ast::Pat, initializer: Option<ast::Expr>) -> ast::LetStmt {
let text = match initializer {
Some(it) => format!("let {} = {};", pattern.syntax(), it.syntax()),
None => format!("let {};", pattern.syntax()),
};
ast_from_text(&format!("fn f() {{ {} }}", text))
}
pub fn token(kind: SyntaxKind) -> SyntaxToken {
tokens::SOURCE_FILE
.tree()
.syntax()
.descendants_with_tokens()
.filter_map(|it| it.into_token())
.find(|it| it.kind() == kind)
.unwrap_or_else(|| panic!("unhandled token: {:?}", kind))
}
fn ast_from_text<N: AstNode>(text: &str) -> N {
let parse = SourceFile::parse(text);
let node = parse.tree().syntax().descendants().find_map(N::cast).unwrap();
let node = node.syntax().clone();
let node = unroot(node);
let node = N::cast(node).unwrap();
assert_eq!(node.syntax().text_range().start(), 0.into());
node
}
fn unroot(n: SyntaxNode) -> SyntaxNode {
SyntaxNode::new_root(n.green().clone())
}
pub mod tokens {
use crate::{AstNode, Parse, SourceFile, SyntaxKind::*, SyntaxToken, T};
use once_cell::sync::Lazy;
pub(super) static SOURCE_FILE: Lazy<Parse<SourceFile>> =
Lazy::new(|| SourceFile::parse("const C: <()>::Item = (1 != 1, 2 == 2)\n;"));
pub fn comma() -> SyntaxToken {
SOURCE_FILE
.tree()
.syntax()
.descendants_with_tokens()
.filter_map(|it| it.into_token())
.find(|it| it.kind() == T![,])
.unwrap()
}
pub fn single_space() -> SyntaxToken {
SOURCE_FILE
.tree()
.syntax()
.descendants_with_tokens()
.filter_map(|it| it.into_token())
.find(|it| it.kind() == WHITESPACE && it.text().as_str() == " ")
.unwrap()
}
pub fn whitespace(text: &str) -> SyntaxToken {
assert!(text.trim().is_empty());
let sf = SourceFile::parse(text).ok().unwrap();
sf.syntax().first_child_or_token().unwrap().into_token().unwrap()
}
pub fn single_newline() -> SyntaxToken {
SOURCE_FILE
.tree()
.syntax()
.descendants_with_tokens()
.filter_map(|it| it.into_token())
.find(|it| it.kind() == WHITESPACE && it.text().as_str() == "\n")
.unwrap()
}
pub struct WsBuilder(SourceFile);
impl WsBuilder {
pub fn new(text: &str) -> WsBuilder {
WsBuilder(SourceFile::parse(text).ok().unwrap())
}
pub fn ws(&self) -> SyntaxToken {
self.0.syntax().first_child_or_token().unwrap().into_token().unwrap()
}
}
}
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