add convert(::Type{Regex}, ::Union{AbstractString,AbstractChar})

base/regex.jl

@@ -542,7 +542,7 @@ function hash(r::Regex, h::UInt)
     h = hash(r.match_options, h)
 end
 
-## String operations ##
+## string operations ##
 
 """
     *(s::Regex, t::Union{Regex,AbstractString,AbstractChar}) -> Regex
@@ -645,3 +645,31 @@ RegexMatch("Test Test ")
 ```
 """
 ^(r::Regex, i::Integer) = Regex(string("(?:", r.pattern, "){$i}"), r.compile_options, r.match_options)
+
+## conversion from strings/chars ##
+
+"""
+    convert(::Type{Regex}, x::AbstractChar)
+    convert(::Type{Regex}, x::AbstractString)
+
+Create a `Regex` which matches `x` exactly. This means that special characters are
+not interpreted as having special meaning.
+Multiplication can also be used in order to create a regex with specific flags.
+
+!!! compat "Julia 1.3"
+     This method requires at least Julia 1.3.
+
+# Examples
+```jldoctest
+julia> match(convert(Regex, '('), "(").match
+"("
+
+julia> match(convert(Regex, ".*"), "abc") == nothing
+true
+
+julia> match(convert(Regex, ".*"), ".*")
+RegexMatch(".*")
+```
+
+"""
+convert(::Type{Regex}, s::Union{AbstractString,AbstractChar}) = Regex(wrap_string(s, zero(UInt32)))

test/regex.jl

@@ -124,6 +124,25 @@
         @test r"this|that"^2 == r"(?:this|that){2}"
     end
 
+    @testset "convert from strings/chars" begin
+        r = convert(Regex, 'a')
+        @test r == r"\Qa\E" # these tests can change if the implementation changes
+        @test match(r, "a").match == "a"
+        r = convert(Regex, '\\')
+        @test r == r"\Q\\E"
+        @test match(r, "\\").match == "\\"
+        r = convert(Regex, '(')
+        @test r == r"\Q(\E"
+        @test match(r, "(").match == "("
+
+        r = convert(Regex, "a\\b(c")
+        @test r == r"\Qa\b(c\E"
+        @test match(r, "a\\b(c").match == "a\\b(c"
+        r = convert(Regex, "a\\E\\Qz")
+        @test r == r"\Qa\\E\QE\Qz\E"
+        @test match(r, "a\\E\\Qz") != nothing
+    end
+
     # Test that PCRE throws the correct kind of error
     # TODO: Uncomment this once the corresponding change has propagated to CI
     #@test_throws ErrorException Base.PCRE.info(C_NULL, Base.PCRE.INFO_NAMECOUNT, UInt32)