Make startswith, endswith work with Regex

base/pcre.jl

@@ -37,6 +37,7 @@ const COMPILE_MASK      =
       CASELESS          |
       DOLLAR_ENDONLY    |
       DOTALL            |
+      ENDANCHORED       |
       EXTENDED          |
       FIRSTLINE         |
       MULTILINE         |

base/regex.jl

@@ -174,6 +174,64 @@ function occursin(r::Regex, s::SubString; offset::Integer=0)
                      r.match_data)
 end
 
+"""
+    startswith(s::AbstractString, prefix::Regex)
+
+Return `true` if `s` starts with the regex pattern, `prefix`.
+
+!!! note
+    `occursin` is recommended over the regex version of `startswith`
+    in performance critical situations.
+
+See also [`occursin`](@ref) and [`endswith`](@ref).
+
+# Examples
+```jldoctest
+julia> startswith("JuliaLang", r"Julia|Romeo")
+true
+```
+"""
+function startswith(s::AbstractString, r::Regex)
+    compile(r)
+    return PCRE.exec(r.regex, String(s), 0, r.match_options | PCRE.ANCHORED,
+                     r.match_data)
+end
+
+function startswith(s::SubString, r::Regex)
+    compile(r)
+    return PCRE.exec(r.regex, s, 0, r.match_options | PCRE.ANCHORED,
+                     r.match_data)
+end
+
+"""
+    endswith(s::AbstractString, suffix::Regex)
+
+Return `true` if `s` ends with the regex pattern, `suffix`.
+
+!!! note
+    `occursin` is recommended over the regex version of `endswith` in
+    performance critical situations.
+
+See also [`occursin`](@ref) and [`startswith`](@ref).
+
+# Examples
+```jldoctest
+julia> endswith("JuliaLang", r"Lang|Roberts")
+true
+```
+"""
+function endswith(s::AbstractString, r::Regex)
+    compile(r)
+    return PCRE.exec(r.regex, String(s), 0, r.match_options | PCRE.ENDANCHORED,
+                     r.match_data)
+end
+
+function endswith(s::SubString, r::Regex)
+    compile(r)
+    return PCRE.exec(r.regex, s, 0, r.match_options | PCRE.ENDANCHORED,
+                     r.match_data)
+end
+
 """
     match(r::Regex, s::AbstractString[, idx::Integer[, addopts]])
 

test/regex.jl

@@ -61,3 +61,15 @@ end
 # 'a' flag to disable UCP
 @test match(r"\w+", "Düsseldorf").match == "Düsseldorf"
 @test match(r"\w+"a, "Düsseldorf").match == "D"
+
+@test startswith("abc", r"a")
+@test endswith("abc", r"c")
+@test !startswith("abc", r"b")
+@test !startswith("abc", r"c")
+@test !endswith("abc", r"a")
+@test !endswith("abc", r"b")
+
+@test !startswith("abc", r"A")
+@test startswith("abc", r"A"i)
+@test !endswith("abc", r"C")
+@test endswith("abc", r"C"i)