1 files changed, 285 insertions, 0 deletions
diff --git a/luaextra-string.lua b/luaextra-string.lua
new file mode 100644
index 0000000..25b8f8e
--- /dev/null
+++ b/luaextra-string.lua
@@ -0,0 +1,285 @@
+if not modules then modules = { } end modules ['l-string'] = {
+    version   = 1.001,
+    comment   = "companion to luat-lib.mkiv",
+    author    = "Hans Hagen, PRAGMA-ADE, Hasselt NL",
+    copyright = "PRAGMA ADE / ConTeXt Development Team",
+    license   = "see context related readme files"
+}
+
+local sub, gsub, find, match, gmatch, format, char, byte, rep, lower = string.sub, string.gsub, string.find, string.match, string.gmatch, string.format, string.char, string.byte, string.rep, string.lower
+local lpegmatch = lpeg.match
+
+-- some functions may disappear as they are not used anywhere
+
+if not string.split then
+
+    -- this will be overloaded by a faster lpeg variant
+
+    function string:split(pattern)
+        if #self > 0 then
+            local t = { }
+            for s in gmatch(self..pattern,"(.-)"..pattern) do
+                t[#t+1] = s
+            end
+            return t
+        else
+            return { }
+        end
+    end
+
+end
+
+local chr_to_esc = {
+    ["%"] = "%%",
+    ["."] = "%.",
+    ["+"] = "%+", ["-"] = "%-", ["*"] = "%*",
+    ["^"] = "%^", ["$"] = "%$",
+    ["["] = "%[", ["]"] = "%]",
+    ["("] = "%(", [")"] = "%)",
+    ["{"] = "%{", ["}"] = "%}"
+}
+
+string.chr_to_esc = chr_to_esc
+
+function string:esc() -- variant 2
+    return (gsub(self,"(.)",chr_to_esc))
+end
+
+function string:unquote()
+    return (gsub(self,"^([\"\'])(.*)%1$","%2"))
+end
+
+--~ function string:unquote()
+--~     if find(self,"^[\'\"]") then
+--~         return sub(self,2,-2)
+--~     else
+--~         return self
+--~     end
+--~ end
+
+function string:quote() -- we could use format("%q")
+    return format("%q",self)
+end
+
+function string:count(pattern) -- variant 3
+    local n = 0
+    for _ in gmatch(self,pattern) do
+        n = n + 1
+    end
+    return n
+end
+
+function string:limit(n,sentinel)
+    if #self > n then
+        sentinel = sentinel or " ..."
+        return sub(self,1,(n-#sentinel)) .. sentinel
+    else
+        return self
+    end
+end
+
+--~ function string:strip() -- the .- is quite efficient
+--~  -- return match(self,"^%s*(.-)%s*$") or ""
+--~  -- return match(self,'^%s*(.*%S)') or '' -- posted on lua list
+--~     return find(s,'^%s*$') and '' or match(s,'^%s*(.*%S)')
+--~ end
+
+do -- roberto's variant:
+    local space    = lpeg.S(" \t\v\n")
+    local nospace  = 1 - space
+    local stripper = space^0 * lpeg.C((space^0 * nospace^1)^0)
+    function string.strip(str)
+        return lpegmatch(stripper,str) or ""
+    end
+end
+
+function string:is_empty()
+    return not find(self,"%S")
+end
+
+function string:enhance(pattern,action)
+    local ok, n = true, 0
+    while ok do
+        ok = false
+        self = gsub(self,pattern, function(...)
+            ok, n = true, n + 1
+            return action(...)
+        end)
+    end
+    return self, n
+end
+
+local chr_to_hex, hex_to_chr = { }, { }
+
+for i=0,255 do
+    local c, h = char(i), format("%02X",i)
+    chr_to_hex[c], hex_to_chr[h] = h, c
+end
+
+function string:to_hex()
+    return (gsub(self or "","(.)",chr_to_hex))
+end
+
+function string:from_hex()
+    return (gsub(self or "","(..)",hex_to_chr))
+end
+
+if not string.characters then
+
+    local function nextchar(str, index)
+        index = index + 1
+        return (index <= #str) and index or nil, sub(str,index,index)
+    end
+    function string:characters()
+        return nextchar, self, 0
+    end
+    local function nextbyte(str, index)
+        index = index + 1
+        return (index <= #str) and index or nil, byte(sub(str,index,index))
+    end
+    function string:bytes()
+        return nextbyte, self, 0
+    end
+
+end
+
+-- we can use format for this (neg n)
+
+function string:rpadd(n,chr)
+    local m = n-#self
+    if m > 0 then
+        return self .. rep(chr or " ",m)
+    else
+        return self
+    end
+end
+
+function string:lpadd(n,chr)
+    local m = n-#self
+    if m > 0 then
+        return rep(chr or " ",m) .. self
+    else
+        return self
+    end
+end
+
+string.padd = string.rpadd
+
+function is_number(str) -- tonumber
+    return find(str,"^[%-%+]?[%d]-%.?[%d+]$") == 1
+end
+
+--~ print(is_number("1"))
+--~ print(is_number("1.1"))
+--~ print(is_number(".1"))
+--~ print(is_number("-0.1"))
+--~ print(is_number("+0.1"))
+--~ print(is_number("-.1"))
+--~ print(is_number("+.1"))
+
+function string:split_settings() -- no {} handling, see l-aux for lpeg variant
+    if find(self,"=") then
+        local t = { }
+        for k,v in gmatch(self,"(%a+)=([^%,]*)") do
+            t[k] = v
+        end
+        return t
+    else
+        return nil
+    end
+end
+
+local patterns_escapes = {
+    ["-"] = "%-",
+    ["."] = "%.",
+    ["+"] = "%+",
+    ["*"] = "%*",
+    ["%"] = "%%",
+    ["("] = "%)",
+    [")"] = "%)",
+    ["["] = "%[",
+    ["]"] = "%]",
+}
+
+function string:pattesc()
+    return (gsub(self,".",patterns_escapes))
+end
+
+local simple_escapes = {
+    ["-"] = "%-",
+    ["."] = "%.",
+    ["?"] = ".",
+    ["*"] = ".*",
+}
+
+function string:simpleesc()
+    return (gsub(self,".",simple_escapes))
+end
+
+function string:tohash()
+    local t = { }
+    for s in gmatch(self,"([^, ]+)") do -- lpeg
+        t[s] = true
+    end
+    return t
+end
+
+local pattern = lpeg.Ct(lpeg.C(1)^0)
+
+function string:totable()
+    return lpegmatch(pattern,self)
+end
+
+--~ for _, str in ipairs {
+--~     "1234567123456712345671234567",
+--~     "a\tb\tc",
+--~     "aa\tbb\tcc",
+--~     "aaa\tbbb\tccc",
+--~     "aaaa\tbbbb\tcccc",
+--~     "aaaaa\tbbbbb\tccccc",
+--~     "aaaaaa\tbbbbbb\tcccccc",
+--~ } do print(string.tabtospace(str)) end
+
+function string.tabtospace(str,tab)
+    -- we don't handle embedded newlines
+    while true do
+        local s = find(str,"\t")
+        if s then
+            if not tab then tab = 7 end -- only when found
+            local d = tab-(s-1) % tab
+            if d > 0 then
+                str = gsub(str,"\t",rep(" ",d),1)
+            else
+                str = gsub(str,"\t","",1)
+            end
+        else
+            break
+        end
+    end
+    return str
+end
+
+function string:compactlong() -- strips newlines and leading spaces
+    self = gsub(self,"[\n\r]+ *","")
+    self = gsub(self,"^ *","")
+    return self
+end
+
+function string:striplong() -- strips newlines and leading spaces
+    self = gsub(self,"^%s*","")
+    self = gsub(self,"[\n\r]+ *","\n")
+    return self
+end
+
+function string:topattern(lowercase,strict)
+    if lowercase then
+        self = lower(self)
+    end
+    self = gsub(self,".",simple_escapes)
+    if self == "" then
+        self = ".*"
+    elseif strict then
+        self = "^" .. self .. "$"
+    end
+    return self
+end