1 files changed, 79 insertions, 0 deletions
diff --git a/string2.moon b/string2.moon
new file mode 100644
index 0000000..735a2cb
--- /dev/null
+++ b/string2.moon
@@ -0,0 +1,79 @@
+-- Expand the capabilities of the built-in strings
+{:reverse, :upper, :lower, :find, :byte, :match, :gmatch, :gsub, :sub, :format, :rep, :char} = string
+
+isplit = (sep='%s+')=>
+    step = (i)=>
+        start = @pos
+        return unless start
+        i += 1
+        nl = find(@str, @sep, start)
+        @pos = nl and (nl+1) or nil
+        line = sub(@str, start, nl and (nl-1) or #@str)
+        return i, line, start, (nl and (nl-1) or #@str)
+    return step, {str:@, pos:1, :sep}, 0
+
+string2 = {
+    :isplit, uppercase:upper, lowercase:lower, reversed:reverse
+    capitalized: => gsub(@, '%l', upper, 1)
+    byte: byte, bytes: (i, j)=> {byte(@, i or 1, j or -1)}
+    split: (sep)=> [chunk for i,chunk in isplit(@, sep)]
+    lines: => [line for i,line in isplit(@, '\n')]
+    line: (line_num)=>
+        for i, line, start in isplit(@, '\n')
+            return line if i == line_num
+
+    line_at: (pos)=>
+        assert(type(pos) == 'number', "Invalid string position")
+        return if pos < 1 or pos > #@
+        for i, line, start, stop in isplit(@, '\n')
+            if stop >= pos
+                return line, i, (pos-start+1)
+
+    wrap: (maxlen=80, buffer=8)=>
+        lines = {}
+        for line in *@lines!
+            while #line > maxlen
+                chunk = line\sub(1, maxlen)
+                split = chunk\find(' ', maxlen-buffer, true) or maxlen
+                chunk = line\sub(1, split)
+                line = line\sub(split+1, -1)
+                lines[#lines+1] = chunk
+            lines[#lines+1] = line
+        return table.concat(lines, "\n")
+
+    -- Convert an arbitrary text into a valid Lua identifier. This function is injective,
+    -- but not idempotent. In logic terms: (x != y) => (as_lua_id(x) != as_lua_id(y)),
+    -- but not (as_lua_id(a) == b) => (as_lua_id(b) == b).
+    as_lua_id: (str)->
+        orig = str
+        -- Empty strings are not valid lua identifiers, so treat them like " ",
+        -- and treat " " as "  ", etc. to preserve injectivity.
+        str = gsub str, "^ *$", "%1 "
+        -- Escape 'x' (\x78) when it precedes something that looks like an uppercase hex sequence.
+        -- This way, all Lua IDs can be unambiguously reverse-engineered, but normal usage
+        -- of 'x' won't produce ugly Lua IDs.
+        -- i.e. "x" -> "x", "oxen" -> "oxen", but "Hex2Dec" -> "Hex782Dec" and "He-ec" -> "Hex2Dec"
+        str = gsub str, "x([0-9A-F][0-9A-F])", "x78%1"
+        -- Map spaces to underscores, and everything else non-alphanumeric to hex escape sequences
+        str = gsub str, "%W", (c)->
+            if c == ' ' then '_'
+            else format("x%02X", byte(c))
+        -- Lua IDs can't start with numbers, so map "1" -> "_1", "_1" -> "__1", etc.
+        str = gsub str, "^_*%d", "_%1"
+        if str.from_lua_id
+            re_orig = str\from_lua_id!
+            require('ldt').breakpoint! if re_orig != orig
+        return str
+
+    -- from_lua_id(as_lua_id(str)) == str, but behavior is unspecified for inputs that
+    -- did not come from as_lua_id()
+    from_lua_id: (str)->
+        str = gsub(str, "^_(_*%d.*)", "%1")
+        str = gsub(str, "_", " ")
+        str = gsub(str, "x([0-9A-F][0-9A-F])", (hex)-> char(tonumber(hex, 16)))
+        str = gsub(str, "^ ([ ]*)$", "%1")
+        return str
+}
+for k,v in pairs(string) do string2[k] or= v
+
+return string2