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< main > < div class = "width-limiter" > < nav class = "sub" > < form class = "search-form" > < span > < / span > < div id = "sidebar-button" tabindex = "-1" > < a href = "../regex/all.html" title = "show sidebar" > < / a > < / div > < input class = "search-input" name = "search" aria-label = "Run search in the documentation" autocomplete = "off" spellcheck = "false" placeholder = "Click or press ‘ ’ ‘ ’ type = "search" > < div id = "help-button" tabindex = "-1" > < a href = "../help.html" title = "help" > ?< / a > < / div > < div id = "settings-menu" tabindex = "-1" > < a href = "../settings.html" title = "settings" > < img width = "22" height = "22" alt = "Change settings" src = "../static.files/wheel-7b819b6101059cd0.svg" > < / a > < / div > < / form > < / nav > < section id = "main-content" class = "content" > < div class = "main-heading" > < h1 > Trait < a href = "index.html" > regex< / a > ::< wbr > < a class = "trait" href = "#" > Replacer< / a > < button id = "copy-path" title = "Copy item path to clipboard" > < img src = "../static.files/clipboard-7571035ce49a181d.svg" width = "19" height = "18" alt = "Copy item path" > < / button > < / h1 > < span class = "out-of-band" > < a class = "src" href = "../src/regex/regex/string.rs.html#2431-2477" > source< / a > · < button id = "toggle-all-docs" title = "collapse all docs" > [< span > − < / span > ]< / button > < / span > < / div > < pre class = "rust item-decl" > < code > pub trait Replacer {
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// Required method
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fn < a href = "#tymethod.replace_append" class = "fn" > replace_append< / a > (& mut self, caps: & < a class = "struct" href = "struct.Captures.html" title = "struct regex::Captures" > Captures< / a > < '_> , dst: & mut < a class = "struct" href = "https://doc.rust-lang.org/1.78.0/alloc/string/struct.String.html" title = "struct alloc::string::String" > String< / a > );
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// Provided methods
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fn < a href = "#method.no_expansion" class = "fn" > no_expansion< / a > < 'r> (& 'r mut self) -> < a class = "enum" href = "https://doc.rust-lang.org/1.78.0/core/option/enum.Option.html" title = "enum core::option::Option" > Option< / a > < < a class = "enum" href = "https://doc.rust-lang.org/1.78.0/alloc/borrow/enum.Cow.html" title = "enum alloc::borrow::Cow" > Cow< / a > < 'r, < a class = "primitive" href = "https://doc.rust-lang.org/1.78.0/std/primitive.str.html" > str< / a > > > { ... }
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< span class = "item-spacer" > < / span > fn < a href = "#method.by_ref" class = "fn" > by_ref< / a > < 'r> (& 'r mut self) -> < a class = "struct" href = "struct.ReplacerRef.html" title = "struct regex::ReplacerRef" > ReplacerRef< / a > < 'r, Self> { ... }
}< / code > < / pre > < details class = "toggle top-doc" open > < summary class = "hideme" > < span > Expand description< / span > < / summary > < div class = "docblock" > < p > A trait for types that can be used to replace matches in a haystack.< / p >
< p > In general, users of this crate shouldn’
since implementations are already provided for < code > & str< / code > along with other
variants of string types, as well as < code > FnMut(& Captures) -> String< / code > (or any
< code > FnMut(& Captures) -> T< / code > where < code > T: AsRef< str> < / code > ). Those cover most use cases,
but callers can implement this trait directly if necessary.< / p >
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< h2 id = "example" > < a class = "doc-anchor" href = "#example" > §< / a > Example< / h2 >
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< p > This example shows a basic implementation of the < code > Replacer< / code > trait. This
can be done much more simply using the replacement string interpolation
support (e.g., < code > $first $last< / code > ), but this approach avoids needing to parse
the replacement string at all.< / p >
< div class = "example-wrap" > < pre class = "rust rust-example-rendered" > < code > < span class = "kw" > use < / span > regex::{Captures, Regex, Replacer};
< span class = "kw" > struct < / span > NameSwapper;
< span class = "kw" > impl < / span > Replacer < span class = "kw" > for < / span > NameSwapper {
< span class = "kw" > fn < / span > replace_append(< span class = "kw-2" > & mut < / span > < span class = "self" > self< / span > , caps: < span class = "kw-2" > & < / span > Captures< < span class = "lifetime" > '_< / span > > , dst: < span class = "kw-2" > & mut < / span > String) {
dst.push_str(< span class = "kw-2" > & < / span > caps[< span class = "string" > "first"< / span > ]);
dst.push_str(< span class = "string" > " "< / span > );
dst.push_str(< span class = "kw-2" > & < / span > caps[< span class = "string" > "last"< / span > ]);
}
}
< span class = "kw" > let < / span > re = Regex::new(< span class = "string" > r"(?< last> [^,\s]+),\s+(?< first> \S+)"< / span > ).unwrap();
< span class = "kw" > let < / span > result = re.replace(< span class = "string" > "Springsteen, Bruce"< / span > , NameSwapper);
< span class = "macro" > assert_eq!< / span > (result, < span class = "string" > "Bruce Springsteen"< / span > );< / code > < / pre > < / div >
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< / div > < / details > < h2 id = "required-methods" class = "section-header" > Required Methods< a href = "#required-methods" class = "anchor" > §< / a > < / h2 > < div class = "methods" > < details class = "toggle method-toggle" open > < summary > < section id = "tymethod.replace_append" class = "method" > < a class = "src rightside" href = "../src/regex/regex/string.rs.html#2438" > source< / a > < h4 class = "code-header" > fn < a href = "#tymethod.replace_append" class = "fn" > replace_append< / a > (& mut self, caps: & < a class = "struct" href = "struct.Captures.html" title = "struct regex::Captures" > Captures< / a > < '_> , dst: & mut < a class = "struct" href = "https://doc.rust-lang.org/1.78.0/alloc/string/struct.String.html" title = "struct alloc::string::String" > String< / a > )< / h4 > < / section > < / summary > < div class = "docblock" > < p > Appends possibly empty data to < code > dst< / code > to replace the current match.< / p >
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< p > The current match is represented by < code > caps< / code > , which is guaranteed to
have a match at capture group < code > 0< / code > .< / p >
< p > For example, a no-op replacement would be < code > dst.push_str(& caps[0])< / code > .< / p >
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< / div > < / details > < / div > < h2 id = "provided-methods" class = "section-header" > Provided Methods< a href = "#provided-methods" class = "anchor" > §< / a > < / h2 > < div class = "methods" > < details class = "toggle method-toggle" open > < summary > < section id = "method.no_expansion" class = "method" > < a class = "src rightside" href = "../src/regex/regex/string.rs.html#2448-2450" > source< / a > < h4 class = "code-header" > fn < a href = "#method.no_expansion" class = "fn" > no_expansion< / a > < 'r> (& 'r mut self) -> < a class = "enum" href = "https://doc.rust-lang.org/1.78.0/core/option/enum.Option.html" title = "enum core::option::Option" > Option< / a > < < a class = "enum" href = "https://doc.rust-lang.org/1.78.0/alloc/borrow/enum.Cow.html" title = "enum alloc::borrow::Cow" > Cow< / a > < 'r, < a class = "primitive" href = "https://doc.rust-lang.org/1.78.0/std/primitive.str.html" > str< / a > > > < / h4 > < / section > < / summary > < div class = "docblock" > < p > Return a fixed unchanging replacement string.< / p >
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< p > When doing replacements, if access to < a href = "struct.Captures.html" title = "struct regex::Captures" > < code > Captures< / code > < / a > is not needed (e.g.,
the replacement string does not need < code > $< / code > expansion), then it can be
beneficial to avoid finding sub-captures.< / p >
< p > In general, this is called once for every call to a replacement routine
such as < a href = "struct.Regex.html#method.replace_all" title = "method regex::Regex::replace_all" > < code > Regex::replace_all< / code > < / a > .< / p >
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< / div > < / details > < details class = "toggle method-toggle" open > < summary > < section id = "method.by_ref" class = "method" > < a class = "src rightside" href = "../src/regex/regex/string.rs.html#2474-2476" > source< / a > < h4 class = "code-header" > fn < a href = "#method.by_ref" class = "fn" > by_ref< / a > < 'r> (& 'r mut self) -> < a class = "struct" href = "struct.ReplacerRef.html" title = "struct regex::ReplacerRef" > ReplacerRef< / a > < 'r, Self> < / h4 > < / section > < / summary > < div class = "docblock" > < p > Returns a type that implements < code > Replacer< / code > , but that borrows and wraps
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this < code > Replacer< / code > .< / p >
< p > This is useful when you want to take a generic < code > Replacer< / code > (which might
not be cloneable) and use it without consuming it, so it can be used
more than once.< / p >
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< h5 id = "example-1" > < a class = "doc-anchor" href = "#example-1" > §< / a > Example< / h5 >
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< div class = "example-wrap" > < pre class = "rust rust-example-rendered" > < code > < span class = "kw" > use < / span > regex::{Regex, Replacer};
< span class = "kw" > fn < / span > replace_all_twice< R: Replacer> (
re: Regex,
src: < span class = "kw-2" > & < / span > str,
< span class = "kw-2" > mut < / span > rep: R,
) -> String {
< span class = "kw" > let < / span > dst = re.replace_all(src, rep.by_ref());
< span class = "kw" > let < / span > dst = re.replace_all(< span class = "kw-2" > & < / span > dst, rep.by_ref());
dst.into_owned()
}< / code > < / pre > < / div >
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< / div > < / details > < / div > < h2 id = "object-safety" class = "section-header" > Object Safety< a href = "#object-safety" class = "anchor" > §< / a > < / h2 > < div class = "object-safety-info" > This trait is < b > not< / b > < a href = "https://doc.rust-lang.org/1.78.0/reference/items/traits.html#object-safety" > object safe< / a > .< / div > < h2 id = "foreign-impls" class = "section-header" > Implementations on Foreign Types< a href = "#foreign-impls" class = "anchor" > §< / a > < / h2 > < details class = "toggle implementors-toggle" > < summary > < section id = "impl-Replacer-for-String" class = "impl" > < a class = "src rightside" href = "../src/regex/regex/string.rs.html#2499-2507" > source< / a > < a href = "#impl-Replacer-for-String" class = "anchor" > §< / a > < h3 class = "code-header" > impl < a class = "trait" href = "trait.Replacer.html" title = "trait regex::Replacer" > Replacer< / a > for < a class = "struct" href = "https://doc.rust-lang.org/1.78.0/alloc/string/struct.String.html" title = "struct alloc::string::String" > String< / a > < / h3 > < / section > < / summary > < div class = "impl-items" > < section id = "method.replace_append" class = "method trait-impl" > < a class = "src rightside" href = "../src/regex/regex/string.rs.html#2500-2502" > source< / a > < a href = "#method.replace_append" class = "anchor" > §< / a > < h4 class = "code-header" > fn < a href = "#tymethod.replace_append" class = "fn" > replace_append< / a > (& mut self, caps: & < a class = "struct" href = "struct.Captures.html" title = "struct regex::Captures" > Captures< / a > < '_> , dst: & mut < a class = "struct" href = "https://doc.rust-lang.org/1.78.0/alloc/string/struct.String.html" title = "struct alloc::string::String" > String< / a > )< / h4 > < / section > < section id = "method.no_expansion-1" class = "method trait-impl" > < a class = "src rightside" href = "../src/regex/regex/string.rs.html#2504-2506" > source< / a > < a href = "#method.no_expansion-1" class = "anchor" > §< / a > < h4 class = "code-header" > fn < a href = "#method.no_expansion" class = "fn" > no_expansion< / a > (& mut self) -> < a class = "enum" href = "https://doc.rust-lang.org/1.78.0/core/option/enum.Option.html" title = "enum core::option::Option" > Option< / a > < < a class = "enum" href = "https://doc.rust-lang.org/1.78.0/alloc/borrow/enum.Cow.html" title = "enum alloc::borrow::Cow" > Cow< / a > < '_, < a class = "primitive" href = "https://doc.rust-lang.org/1.78.0/std/primitive.str.html" > str< / a > > > < / h4 > < / section > < / div > < / details > < details class = "toggle implementors-toggle" > < summary > < section id = "impl-Replacer-for-%26Cow%3C'a,+str%3E" class = "impl" > < a class = "src rightside" href = "../src/regex/regex/string.rs.html#2519-2527" > source< / a > < a href = "#impl-Replacer-for-%26Cow%3C'a,+str%3E" class = "anchor" > §< / a > < h3 class = "code-header" > impl< 'a> < a class = "trait" href = "trait.Replacer.html" title = "trait regex::Replacer" > Replacer< / a > for & 'a < a class = "enum" href = "https://doc.rust-lang.org/1.78.0/alloc/borrow/enum.Cow.html" title = "enum alloc::borrow::Cow" > Cow< / a > < 'a, < a class = "primitive" href = "https://doc.rust-lang.org/1.78.0/std/primitive.str.html" > str< / a > > < / h3 > < / section > < / summary > < div class = "impl-items" > < section id = "method.replace_append-1" class = "method trait-impl" > < a class = "src rightside" href = "../src/regex/regex/string.rs.html#2520-2522" > source< / a > < a href = "#method.replace_append-1" class = "anchor" > §< / a > < h4 class = "code-header" > fn < a href = "#tymethod.replace_append" class = "fn" > replace_append< / a > (& mut self, caps: & < a class = "struct" href = "struct.Captures.html" title = "struct regex::Captures" > Captures< / a > < '_> , dst: & mut < a class = "struct" href = "https://doc.rust-lang.org/1.78.0/alloc/string/struct.String.html" title = "struct alloc::string::String" > String< / a > )< / h4 > < / section > < section id = "method.no_expansion-2" class = "method trait-impl" > < a class = "src rightside" href = "../src/regex/regex/string.rs.html#2524-2526" > source< / a > < a href = "#method.no_expansion-2" class = "anchor" > §< / a > < h4 class = "code-header" > fn < a href = "#method.no_expansion" class = "fn" > no_expansion< / a > (& mut self) -> < a class = "enum" href = "https://doc.rust-lang.org/1.78.0/core/option/enum.Option.html" title = "enum core::option::Option" > Option< / a > < < a class = "enum" href = "https://doc.rust-lang.org/1.78.0/alloc/borrow/enum.Cow.html" title = "enum alloc::borr
F: < a class = "trait" href = "https://doc.rust-lang.org/1.78.0/core/ops/function/trait.FnMut.html" title = "trait core::ops::function::FnMut" > FnMut< / a > (& < a class = "struct" href = "struct.Captures.html" title = "struct regex::Captures" > Captures< / a > < '_> ) -> T,
T: < a class = "trait" href = "https://doc.rust-lang.org/1.78.0/core/convert/trait.AsRef.html" title = "trait core::convert::AsRef" > AsRef< / a > < < a class = "primitive" href = "https://doc.rust-lang.org/1.78.0/std/primitive.str.html" > str< / a > > ,< / div > < / h3 > < / section > < / div > < script src = "../trait.impl/regex/regex/string/trait.Replacer.js" data-ignore-extern-crates = "alloc,std" async > < / script > < / section > < / div > < / main > < / body > < / html >
