//! This module contains free-standing functions for creating AST fragments out //! of smaller pieces. //! //! Note that all functions here intended to be stupid constructors, which just //! assemble a finish node from immediate children. If you want to do something //! smarter than that, it probably doesn't belong in this module. use itertools::Itertools; use stdx::format_to; 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 type_ref(text: &str) -> ast::TypeRef { ast_from_text(&format!("impl {} for D {{}};", text)) } pub fn path_segment(name_ref: ast::NameRef) -> ast::PathSegment { ast_from_text(&format!("use {};", name_ref)) } pub fn path_unqualified(segment: ast::PathSegment) -> ast::Path { path_from_text(&format!("use {}", segment)) } pub fn path_qualified(qual: ast::Path, segment: ast::PathSegment) -> ast::Path { path_from_text(&format!("{}::{}", qual, segment)) } fn path_from_text(text: &str) -> ast::Path { ast_from_text(text) } pub fn use_tree( path: ast::Path, use_tree_list: Option<ast::UseTreeList>, alias: Option<ast::Alias>, add_star: bool, ) -> ast::UseTree { let mut buf = "use ".to_string(); buf += &path.syntax().to_string(); if let Some(use_tree_list) = use_tree_list { format_to!(buf, "::{}", use_tree_list); } if add_star { buf += "::*"; } if let Some(alias) = alias { format_to!(buf, " {}", alias); } ast_from_text(&buf) } pub fn use_tree_list(use_trees: impl IntoIterator<Item = ast::UseTree>) -> ast::UseTreeList { let use_trees = use_trees.into_iter().map(|it| it.syntax().clone()).join(", "); ast_from_text(&format!("use {{{}}};", use_trees)) } pub fn use_item(use_tree: ast::UseTree) -> ast::UseItem { ast_from_text(&format!("use {};", use_tree)) } pub fn record_field(name: ast::NameRef, expr: Option<ast::Expr>) -> ast::RecordField { return match expr { Some(expr) => from_text(&format!("{}: {}", name, expr)), None => from_text(&name.to_string()), }; fn from_text(text: &str) -> ast::RecordField { ast_from_text(&format!("fn f() {{ S {{ {}, }} }}", text)) } } pub fn record_field_def(name: ast::NameRef, ty: ast::TypeRef) -> ast::RecordFieldDef { ast_from_text(&format!("struct S {{ {}: {}, }}", name, ty)) } pub fn block_expr( stmts: impl IntoIterator<Item = ast::Stmt>, tail_expr: Option<ast::Expr>, ) -> ast::BlockExpr { let mut buf = "{\n".to_string(); for stmt in stmts.into_iter() { format_to!(buf, " {}\n", stmt); } if let Some(tail_expr) = tail_expr { format_to!(buf, " {}\n", tail_expr) } buf += "}"; ast_from_text(&format!("fn f() {}", buf)) } pub fn expr_unit() -> ast::Expr { expr_from_text("()") } pub fn expr_empty_block() -> ast::Expr { expr_from_text("{}") } pub fn expr_unimplemented() -> ast::Expr { expr_from_text("unimplemented!()") } pub fn expr_unreachable() -> ast::Expr { expr_from_text("unreachable!()") } pub fn expr_todo() -> ast::Expr { expr_from_text("todo!()") } pub fn expr_path(path: ast::Path) -> ast::Expr { expr_from_text(&path.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, match_arm_list)) } pub fn expr_if(condition: ast::Condition, then_branch: ast::BlockExpr) -> ast::Expr { expr_from_text(&format!("if {} {}", condition, then_branch)) } pub fn expr_prefix(op: SyntaxKind, expr: ast::Expr) -> ast::Expr { let token = token(op); expr_from_text(&format!("{}{}", token, expr)) } fn expr_from_text(text: &str) -> ast::Expr { ast_from_text(&format!("const C: () = {};", text)) } pub fn try_expr_from_text(text: &str) -> Option<ast::Expr> { try_ast_from_text(&format!("const C: () = {};", text)) } pub fn condition(expr: ast::Expr, pattern: Option<ast::Pat>) -> ast::Condition { match pattern { None => ast_from_text(&format!("const _: () = while {} {{}};", expr)), Some(pattern) => { ast_from_text(&format!("const _: () = while let {} = {} {{}};", pattern, expr)) } } } 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)) } } /// Creates a tuple of patterns from an interator of patterns. /// /// Invariant: `pats` must be length > 1 /// /// FIXME handle `pats` length == 1 pub fn tuple_pat(pats: impl IntoIterator<Item = ast::Pat>) -> ast::TuplePat { let pats_str = pats.into_iter().map(|p| p.to_string()).join(", "); return from_text(&format!("({})", pats_str)); fn from_text(text: &str) -> ast::TuplePat { 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().join(", "); return from_text(&format!("{}({})", path, 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().join(", "); return from_text(&format!("{} {{ {} }}", path, 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 { return from_text(&path.to_string()); 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().join(" | "); return from_text(&format!("{} => {}", pats_str, expr)); 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(&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().join(" + "); return from_text(&format!("{}: {}", path, 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().join(", "); return from_text(preds.as_str()); fn from_text(text: &str) -> ast::WhereClause { ast_from_text(&format!("fn f() where {} {{ }}", text)) } } pub fn let_stmt(pattern: ast::Pat, initializer: Option<ast::Expr>) -> ast::LetStmt { let text = match initializer { Some(it) => format!("let {} = {};", pattern, it), None => format!("let {};", pattern), }; ast_from_text(&format!("fn f() {{ {} }}", text)) } pub fn expr_stmt(expr: ast::Expr) -> ast::ExprStmt { let semi = if expr.is_block_like() { "" } else { ";" }; ast_from_text(&format!("fn f() {{ {}{} (); }}", expr, semi)) } 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)) } pub fn param(name: String, ty: String) -> ast::Param { ast_from_text(&format!("fn f({}: {}) {{ }}", name, ty)) } pub fn param_list(pats: impl IntoIterator<Item = ast::Param>) -> ast::ParamList { let args = pats.into_iter().join(", "); ast_from_text(&format!("fn f({}) {{ }}", args)) } pub fn visibility_pub_crate() -> ast::Visibility { ast_from_text("pub(crate) struct S") } pub fn fn_def( visibility: Option<ast::Visibility>, fn_name: ast::Name, type_params: Option<ast::TypeParamList>, params: ast::ParamList, body: ast::BlockExpr, ) -> ast::FnDef { let type_params = if let Some(type_params) = type_params { format!("<{}>", type_params) } else { "".into() }; let visibility = match visibility { None => String::new(), Some(it) => format!("{} ", it), }; ast_from_text(&format!("{}fn {}{}{} {}", visibility, fn_name, type_params, params, body)) } fn ast_from_text<N: AstNode>(text: &str) -> N { let parse = SourceFile::parse(text); let node = match parse.tree().syntax().descendants().find_map(N::cast) { Some(it) => it, None => { panic!("Failed to make ast node `{}` from text {}", std::any::type_name::<N>(), text) } }; 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 try_ast_from_text<N: AstNode>(text: &str) -> Option<N> { let parse = SourceFile::parse(text); let node = parse.tree().syntax().descendants().find_map(N::cast)?; let node = node.syntax().clone(); let node = unroot(node); let node = N::cast(node).unwrap(); assert_eq!(node.syntax().text_range().start(), 0.into()); Some(node) } fn unroot(n: SyntaxNode) -> SyntaxNode { SyntaxNode::new_root(n.green().clone()) } pub mod tokens { use once_cell::sync::Lazy; use crate::{ast, AstNode, Parse, SourceFile, SyntaxKind::*, SyntaxToken}; pub(super) static SOURCE_FILE: Lazy<Parse<SourceFile>> = Lazy::new(|| SourceFile::parse("const C: <()>::Item = (1 != 1, 2 == 2, !true)\n;")); 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 doc_comment(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 literal(text: &str) -> SyntaxToken { assert_eq!(text.trim(), text); let lit: ast::Literal = super::ast_from_text(&format!("fn f() {{ let _ = {}; }}", text)); lit.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() } } }