diff --git a/base/ascii.jl b/base/ascii.jl
index aff488b33617f..6f94f56082757 100644
--- a/base/ascii.jl
+++ b/base/ascii.jl
@@ -70,7 +70,7 @@ end
 ## outputing ASCII strings ##
 
 print(io::IO, s::ASCIIString) = (write(io, s.data);nothing)
-write(io, s::ASCIIString) = write(io, s.data)
+write(io::IO, s::ASCIIString) = write(io, s.data)
 
 ## transcoding to ASCII ##
 
diff --git a/base/printf.jl b/base/printf.jl
index d5a243a0349dd..800d97a7345ae 100644
--- a/base/printf.jl
+++ b/base/printf.jl
@@ -139,9 +139,9 @@ function _special_handler(flags::ASCIIString, width::Int)
     pos = contains(flags,'+') ? "+" :
           contains(flags,' ') ? " " : ""
     abn = quote
-        isnan($x) ? $(bytestring(pad("NaN", width))) :
-         $x < 0   ? $(bytestring(pad("-Inf", width))) :
-                    $(bytestring(pad("$(pos)Inf", width)))
+        isnan($x) ? $(pad("NaN", width)) :
+         $x < 0   ? $(pad("-Inf", width)) :
+                    $(pad("$(pos)Inf", width))
     end
     ex = :(isfinite($x) ? $blk : write(out, $abn))
     x, ex, blk
diff --git a/base/regex.jl b/base/regex.jl
index 29a84a60d4563..bb9158d359214 100644
--- a/base/regex.jl
+++ b/base/regex.jl
@@ -112,7 +112,8 @@ function search(str::ByteString, re::Regex, idx::Integer)
     m, n = PCRE.exec(re.regex, re.extra, str, idx-1, opts, true)
     isempty(m) ? (0,0) : (m[1]+1,m[2]+1)
 end
-search(s::ByteString, r::Regex) = search(s,r,start(s))
+search(s::String, r::Regex, idx::Integer) = error("regex search is only available for bytestrings; use bytestring(s) to convert")
+search(s::String, r::Regex) = search(s,r,start(s))
 
 type RegexMatchIterator
     regex::Regex
diff --git a/base/set.jl b/base/set.jl
index 4b7f4046f605d..f1c23cb9fa0ec 100644
--- a/base/set.jl
+++ b/base/set.jl
@@ -16,6 +16,7 @@ elements(s::Set) = keys(s.hash)
 eltype{T}(s::Set{T}) = T
 
 has(s::Set, x) = has(s.hash, x)
+contains(s::Set, x) = has(s, x)
 get(s::Set, x, deflt) = get(s.hash, x, false)
 
 add(s::Set, x) = (s.hash[x] = true; s)
diff --git a/base/string.jl b/base/string.jl
index d9aececb9c864..6ac97bab5e390 100644
--- a/base/string.jl
+++ b/base/string.jl
@@ -63,6 +63,7 @@ ref(s::String, v::AbstractVector) =
 symbol(s::String) = symbol(bytestring(s))
 
 print(io::IO, s::String) = for c in s write(io, c) end
+write(io::IO, s::String) = print(io, s)
 show(io::IO, s::String) = print_quoted(io, s)
 
 (*)(s::String...) = strcat(s...)
@@ -156,7 +157,7 @@ function chr2ind(s::String, i::Integer)
     end
 end
 
-typealias Chars Union(Char,AbstractVector{Char})
+typealias Chars Union(Char,AbstractVector{Char},Set{Char})
 
 function strchr(s::String, c::Chars, i::Integer)
     if i < 1 error("index out of range") end
@@ -174,7 +175,15 @@ strchr(s::String, c::Chars) = strchr(s,c,start(s))
 
 contains(s::String, c::Char) = (strchr(s,c)!=0)
 
-search(s::String, c::Chars, i::Integer) = (i=strchr(s,c,i); (i,nextind(s,i)))
+function search(s::String, c::Chars, i::Integer)
+    if isempty(c)
+        return 1 <= i <= length(s)+1 ? (i,i) :
+               i == length(s)+2      ? (0,0) :
+               error("index out of range")
+    end
+    i=strchr(s,c,i)
+    (i, nextind(s,i))
+end
 search(s::String, c::Chars) = search(s,c,start(s))
 
 function search(s::String, t::String, i::Integer)
@@ -447,6 +456,8 @@ strcat(xs...) = string(xs...)  # backwards compat
 
 print(io::IO, s::RopeString) = print(io, s.head, s.tail)
 
+write(io::IO, s::RopeString) = (write(io, s.head); write(io, s.tail))
+
 ## transformed strings ##
 
 type TransformedString <: String
@@ -465,17 +476,57 @@ end
 
 ## uppercase and lowercase transformations ##
 
+const _TF_U = (c,i)->uppercase(c)
+const _TF_L = (c,i)->lowercase(c)
+const _TF_u = (c,i)->i==1 ? uppercase(c) : c
+const _TF_l = (c,i)->i==1 ? lowercase(c) : c
+const _TF_C = (c,i)->i==1 ? uppercase(c) : lowercase(c)
+const _TF_c = (c,i)->i==1 ? lowercase(c) : uppercase(c)
+
 uppercase(c::Char) = ccall(:towupper, Char, (Char,), c)
 lowercase(c::Char) = ccall(:towlower, Char, (Char,), c)
 
 uppercase(c::Uint8) = ccall(:toupper, Uint8, (Uint8,), c)
 lowercase(c::Uint8) = ccall(:tolower, Uint8, (Uint8,), c)
 
-uppercase(s::String) = TransformedString((c,i)->uppercase(c), s)
-lowercase(s::String) = TransformedString((c,i)->lowercase(c), s)
+uppercase(s::String) = TransformedString(_TF_U, s)
+lowercase(s::String) = TransformedString(_TF_L, s)
 
-ucfirst(s::String) = TransformedString((c,i)->i==1 ? uppercase(c) : c, s)
-lcfirst(s::String) = TransformedString((c,i)->i==1 ? lowercase(c) : c, s)
+ucfirst(s::String) = TransformedString(_TF_u, s)
+lcfirst(s::String) = TransformedString(_TF_l, s)
+
+function _transfunc_compose(f2::Function, f1::Function)
+    allf = [_TF_U, _TF_L, _TF_u, _TF_l, _TF_C, _TF_c]
+    if !contains(allf, f2) || !contains(allf, f1)
+        return nothing
+    end
+    if f2 == _TF_U || f2 == _TF_L || f2 == _TF_C || f2 == _TF_c ||
+            f2 == f1 ||
+            (f2 == _TF_u && f1 == _TF_l) ||
+            (f2 == _TF_l && f1 == _TF_u)
+        return f2
+    elseif (f2 == _TF_u && (f1 == _TF_U || f1 == _TF_C)) ||
+           (f2 == _TF_l && (f1 == _TF_L || f1 == _TF_c))
+        return f1
+    elseif (f2 == _TF_u && f1 == _TF_L)
+        return _TF_C
+    elseif (f2 == _TF_l && f1 == _TF_U)
+        return _TF_c
+    elseif (f2 == _TF_u && f1 == _TF_c)
+        return _TF_U
+    elseif (f2 == _TF_l && f1 == _TF_C)
+        return _TF_L
+    end
+    error("this is a bug")
+end
+
+function TransformedString(transform::Function, s::TransformedString)
+    newtf = _transfunc_compose(transform, s.transform)
+    if newtf === nothing
+        return invoke(TransformedString, (Function, String), transform, s)
+    end
+    TransformedString(newtf, s.string)
+end
 
 const uc = uppercase
 const lc = lowercase
@@ -500,7 +551,7 @@ function filter(f::Function, s::String)
     takebuf_string(out)
 end
 
-has(s::String, c::Char) = has(Set(s...), c)
+has(s::String, c::Char) = contains(s, c)
 
 ## string promotion rules ##
 
@@ -864,7 +915,7 @@ function lpad(s::String, n::Integer, p::String)
     if m <= 0; return s; end
     l = strlen(p)
     if l==1
-        return p^m * s
+        return bytestring(p^m * s)
     end
     q = div(m,l)
     r = m - q*l
@@ -876,7 +927,7 @@ function rpad(s::String, n::Integer, p::String)
     if m <= 0; return s; end
     l = strlen(p)
     if l==1
-        return s * p^m
+        return bytestring(s * p^m)
     end
     q = div(m,l)
     r = m - q*l
diff --git a/base/utf8.jl b/base/utf8.jl
index 4e964ed377b7a..29c46bc65f443 100644
--- a/base/utf8.jl
+++ b/base/utf8.jl
@@ -94,7 +94,7 @@ lcfirst(s::UTF8String) = string(lowercase(s[1]), s[2:])
 ## outputing UTF-8 strings ##
 
 print(io::IO, s::UTF8String) = (write(io, s.data);nothing)
-write(io, s::UTF8String) = write(io, s.data)
+write(io::IO, s::UTF8String) = write(io, s.data)
 
 ## transcoding to UTF-8 ##
 
diff --git a/doc/helpdb.jl b/doc/helpdb.jl
index 010d2891cf0fc..b58aeb4482f25 100644
--- a/doc/helpdb.jl
+++ b/doc/helpdb.jl
@@ -549,21 +549,36 @@ collection[key...] = value
 
 "),
 
-(E"Strings",E"ASCIIString",E"ASCIIString(::Array{Uint8, 1})
+(E"Strings",E"ascii",E"ascii(::Array{Uint8, 1})
 
    Create an ASCII string from a byte array.
 
 "),
 
-(E"Strings",E"UTF8String",E"UTF8String(::Array{Uint8, 1})
+(E"Strings",E"ascii",E"ascii(s)
+
+   Convert a string to a contiguous ASCII string (all characters must
+   be valid ASCII characters).
+
+"),
+
+(E"Strings",E"utf8",E"utf8(::Array{Uint8, 1})
 
    Create a UTF-8 string from a byte array.
 
 "),
 
+(E"Strings",E"utf8",E"utf8(s)
+
+   Convert a string to a contiguous UTF-8 string (all characters must
+   be valid UTF-8 characters).
+
+"),
+
 (E"Strings",E"strchr",E"strchr(string, char[, i])
 
    Return the index of 'char' in 'string', giving 0 if not found. The
+   second argument may also be a vector or a set of characters. The
    third argument optionally specifies a starting index.
 
 "),
@@ -582,12 +597,29 @@ collection[key...] = value
 
 "),
 
-(E"Strings",E"split",E"split(string, char, include_empty)
+(E"Strings",E"search",E"search(string, chars[, start])
+
+   Search for the given characters within the given string. The second
+   argument may be a single character, a vector or a set of
+   characters, a string, or a regular expression (but regular
+   expressions are only allowed on contiguous strings, such as ASCII
+   or UTF-8 strings). The third argument optionally specifies a
+   starting index. The return value is a tuple with 2 integers: the
+   index of the match and the first valid index past the match (or an
+   index beyond the end of the string if the match is at the end); it
+   returns '(0,0)' if no match was found, and '(start,start)' if
+   'chars' is empty.
+
+"),
+
+(E"Strings",E"split",E"split(string, chars[, limit][, include_empty])
 
    Return an array of strings by splitting the given string on
-   occurrences of the given character delimiter. The second argument
-   may also be a set of character delimiters to use. The third
-   argument specifies whether empty fields should be included.
+   occurrences of the given character delimiters, which may be
+   specified in any of the formats allowed by 'search''s second
+   argument. The last two arguments are optional; they are are a
+   maximum size for the result and a flag determining whether empty
+   fields should be included in the result.
 
 "),
 
diff --git a/doc/manual/metaprogramming.rst b/doc/manual/metaprogramming.rst
index 80eb56b7fb63d..5cf565370c1dc 100644
--- a/doc/manual/metaprogramming.rst
+++ b/doc/manual/metaprogramming.rst
@@ -275,7 +275,7 @@ cause a compile-time error:
 ::
 
     julia> $a + b
-    not supported
+    unsupported or misplaced expression $
 
 .. _man-macros:
 
diff --git a/doc/stdlib/base.rst b/doc/stdlib/base.rst
index 9121cb5dc17c0..8ff9d7675af9d 100644
--- a/doc/stdlib/base.rst
+++ b/doc/stdlib/base.rst
@@ -401,17 +401,25 @@ Strings
 
    Convert a string to a contiguous byte array representation appropriate for passing it to C functions.
 
-.. function:: ASCIIString(::Array{Uint8,1})
+.. function:: ascii(::Array{Uint8,1})
 
    Create an ASCII string from a byte array.
 
-.. function:: UTF8String(::Array{Uint8,1})
+.. function:: ascii(s)
+
+   Convert a string to a contiguous ASCII string (all characters must be valid ASCII characters).
+
+.. function:: utf8(::Array{Uint8,1})
 
    Create a UTF-8 string from a byte array.
 
+.. function:: utf8(s)
+
+   Convert a string to a contiguous UTF-8 string (all characters must be valid UTF-8 characters).
+
 .. function:: strchr(string, char[, i])
 
-   Return the index of ``char`` in ``string``, giving 0 if not found. The third argument optionally specifies a starting index.
+   Return the index of ``char`` in ``string``, giving 0 if not found. The second argument may also be a vector or a set of characters. The third argument optionally specifies a starting index.
 
 .. function:: lpad(string, n, p)
 
@@ -421,9 +429,13 @@ Strings
 
    Make a string at least ``n`` characters long by padding on the right with copies of ``p``.
 
-.. function:: split(string, char, include_empty)
+.. function:: search(string, chars[, start])
+
+   Search for the given characters within the given string. The second argument may be a single character, a vector or a set of characters, a string, or a regular expression (but regular expressions are only allowed on contiguous strings, such as ASCII or UTF-8 strings). The third argument optionally specifies a starting index. The return value is a tuple with 2 integers: the index of the match and the first valid index past the match (or an index beyond the end of the string if the match is at the end); it returns ``(0,0)`` if no match was found, and ``(start,start)`` if ``chars`` is empty.
+
+.. function:: split(string, chars[, limit][, include_empty])
 
-   Return an array of strings by splitting the given string on occurrences of the given character delimiter. The second argument may also be a set of character delimiters to use. The third argument specifies whether empty fields should be included.
+   Return an array of strings by splitting the given string on occurrences of the given character delimiters, which may be specified in any of the formats allowed by ``search``'s second argument. The last two arguments are optional; they are are a maximum size for the result and a flag determining whether empty fields should be included in the result.
 
 .. function:: strip(string)