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|
use ra_syntax::{
ast::{self, AstNode},
SyntaxKind::WHITESPACE,
SyntaxNode, TextUnit,
};
use crate::assists::{AssistCtx, Assist};
pub fn introduce_variable<'a>(ctx: AssistCtx) -> Option<Assist> {
let node = ctx.covering_node();
let expr = node.ancestors().filter_map(ast::Expr::cast).next()?;
let anchor_stmt = anchor_stmt(expr)?;
let indent = anchor_stmt.prev_sibling()?;
if indent.kind() != WHITESPACE {
return None;
}
ctx.build("introduce variable", move |edit| {
let mut buf = String::new();
buf.push_str("let var_name = ");
expr.syntax().text().push_to(&mut buf);
let is_full_stmt = if let Some(expr_stmt) = ast::ExprStmt::cast(anchor_stmt) {
Some(expr.syntax()) == expr_stmt.expr().map(|e| e.syntax())
} else {
false
};
if is_full_stmt {
edit.replace(expr.syntax().range(), buf);
} else {
buf.push_str(";");
indent.text().push_to(&mut buf);
edit.replace(expr.syntax().range(), "var_name".to_string());
edit.insert(anchor_stmt.range().start(), buf);
}
edit.set_cursor(anchor_stmt.range().start() + TextUnit::of_str("let "));
})
}
/// Statement or last in the block expression, which will follow
/// the freshly introduced var.
fn anchor_stmt(expr: &ast::Expr) -> Option<&SyntaxNode> {
expr.syntax().ancestors().find(|&node| {
if ast::Stmt::cast(node).is_some() {
return true;
}
if let Some(expr) = node
.parent()
.and_then(ast::Block::cast)
.and_then(|it| it.expr())
{
if expr.syntax() == node {
return true;
}
}
false
})
}
#[cfg(test)]
mod tests {
use super::*;
use crate::assists::check_assist_range;
#[test]
fn test_introduce_var_simple() {
check_assist_range(
introduce_variable,
"
fn foo() {
foo(<|>1 + 1<|>);
}",
"
fn foo() {
let <|>var_name = 1 + 1;
foo(var_name);
}",
);
}
#[test]
fn test_introduce_var_expr_stmt() {
check_assist_range(
introduce_variable,
"
fn foo() {
<|>1 + 1<|>;
}",
"
fn foo() {
let <|>var_name = 1 + 1;
}",
);
}
#[test]
fn test_introduce_var_part_of_expr_stmt() {
check_assist_range(
introduce_variable,
"
fn foo() {
<|>1<|> + 1;
}",
"
fn foo() {
let <|>var_name = 1;
var_name + 1;
}",
);
}
#[test]
fn test_introduce_var_last_expr() {
check_assist_range(
introduce_variable,
"
fn foo() {
bar(<|>1 + 1<|>)
}",
"
fn foo() {
let <|>var_name = 1 + 1;
bar(var_name)
}",
);
}
#[test]
fn test_introduce_var_last_full_expr() {
check_assist_range(
introduce_variable,
"
fn foo() {
<|>bar(1 + 1)<|>
}",
"
fn foo() {
let <|>var_name = bar(1 + 1);
var_name
}",
);
}
#[test]
fn test_introduce_var_block_expr_second_to_last() {
check_assist_range(
introduce_variable,
"
fn foo() {
<|>{ let x = 0; x }<|>
something_else();
}",
"
fn foo() {
let <|>var_name = { let x = 0; x };
something_else();
}",
);
}
}
|
