simplify markdown by defining IOBuffer for SubString

Author: hayd

Diff for: base/markdown/GitHub/GitHub.jl

@@ -89,7 +89,7 @@ function github_table(stream::IO, md::MD, config::Config)
                 end
 
             elseif n == 1 || length(rows[1]) == length(row)
-                push!(rows, Row(map(x -> parseinline(IOBuffer(_full(x)), config), row)))
+                push!(rows, Row(map(x -> parseinline(IOBuffer(x), config), row)))
             elseif length(row) > 1
                 seek(stream, pos)
                 break
@@ -107,9 +107,6 @@ function github_table(stream::IO, md::MD, config::Config)
     end
 end
 
-_full{T}(s::SubString{T}) = convert(T, s)
-_full(s::AbstractString) = s
-
 @flavor github [list, indentcode, blockquote, fencedcode, hashheader,
                 github_paragraph, github_table,
                 en_dash, inline_code, asterisk_bold, asterisk_italic, image, link]

Diff for: base/string.jl

@@ -588,6 +588,8 @@ write{T<:ByteString}(to::IOBuffer, s::SubString{T}) =
     s.endof==0 ? 0 : write_sub(to, s.string.data, s.offset+1, next(s,s.endof)[2]-1)
 print(io::IOBuffer, s::SubString) = write(io, s)
 
+IOBuffer(s::SubString) = IOBuffer(s.string.data[s.offset:s.endof], true, false)
+
 sizeof(s::SubString{ASCIIString}) = s.endof
 sizeof(s::SubString{UTF8String}) = s.endof == 0 ? 0 : next(s,s.endof)[2]-1