86 lines
2.4 KiB
Rust
86 lines
2.4 KiB
Rust
use hir::db::HirDatabase;
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use ra_syntax::ast::{self, AstNode};
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use ra_syntax::{TextRange, TextUnit};
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use crate::{Assist, AssistCtx, AssistId};
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use super::apply_demorgan::undo_negation;
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// Assist: invert_if
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//
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// Apply invert_if
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// This transforms if expressions of the form `if !x {A} else {B}` into `if x {B} else {A}`
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// This also works with `!=`. This assist can only be applied with the cursor
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// on `if`.
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//
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// ```
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// fn main() {
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// if<|> !y {A} else {B}
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// }
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// ```
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// ->
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// ```
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// fn main() {
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// if y {B} else {A}
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// }
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// ```
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pub(crate) fn invert_if(ctx: AssistCtx<impl HirDatabase>) -> Option<Assist> {
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let expr = ctx.find_node_at_offset::<ast::IfExpr>()?;
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let expr_range = expr.syntax().text_range();
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let if_range = TextRange::offset_len(expr_range.start(), TextUnit::from_usize(2));
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let cursor_in_range = ctx.frange.range.is_subrange(&if_range);
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if !cursor_in_range {
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return None;
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}
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let cond = expr.condition()?.expr()?.syntax().clone();
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let then_node = expr.then_branch()?.syntax().clone();
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if let ast::ElseBranch::Block(else_block) = expr.else_branch()? {
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let flip_cond = undo_negation(cond.clone())?;
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let cond_range = cond.text_range();
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let else_node = else_block.syntax();
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let else_range = else_node.text_range();
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let then_range = then_node.text_range();
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ctx.add_assist(AssistId("invert_if"), "invert if branches", |edit| {
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edit.target(if_range);
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edit.replace(cond_range, flip_cond);
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edit.replace(else_range, then_node.text());
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edit.replace(then_range, else_node.text());
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})
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} else {
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None
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}
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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use crate::helpers::{check_assist, check_assist_not_applicable};
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#[test]
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fn invert_if_remove_inequality() {
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check_assist(invert_if, "fn f() { i<|>f x != 3 {1} else {3 + 2} }", "fn f() { i<|>f x == 3 {3 + 2} else {1} }")
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}
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#[test]
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fn invert_if_remove_not() {
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check_assist(invert_if, "fn f() { <|>if !cond {3 * 2} else {1} }", "fn f() { <|>if cond {1} else {3 * 2} }")
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}
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#[test]
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fn invert_if_doesnt_apply_with_cursor_not_on_if() {
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check_assist_not_applicable(invert_if, "fn f() { if !<|>cond {3 * 2} else {1} }")
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}
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#[test]
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fn invert_if_doesnt_apply_without_negated() {
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check_assist_not_applicable(invert_if, "fn f() { i<|>f cond {3 * 2} else {1} }")
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}
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}
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