beta 2010.11.19 22:50

1 files changed, 77 insertions, 0 deletions

diff --git a/tex/context/base/util-str.lua b/tex/context/base/util-str.lua
new file mode 100644
index 000000000..18caa27bd
--- /dev/null
+++ b/tex/context/base/util-str.lua
@@ -0,0 +1,77 @@
+if not modules then modules = { } end modules ['util-str'] = {
+    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"
+}
+
+utilities         = utilities or {}
+utilities.strings = utilities.strings or { }
+local strings     = utilities.strings
+
+local find, gsub = string.find, string.gsub
+local patterns, Cs, lpegmatch = lpeg.patterns, lpeg.Cs, lpeg.match
+
+-- str = " \n \ntest  \n test\ntest "
+-- print("["..string.gsub(string.collapsecrlf(str),"\n","+").."]")
+
+local rubish     = patterns.spaceortab^0 * patterns.newline
+local anyrubish  = patterns.spaceortab + patterns.newline
+local anything   = patterns.anything
+local stripped   = (patterns.spaceortab^1 / "") * patterns.newline
+local leading    = rubish^0 / ""
+local trailing   = (anyrubish^1 * patterns.endofstring) / ""
+local redundant  = rubish^3 / "\n"
+
+local pattern = Cs(leading * (trailing + redundant + stripped + anything)^0)
+
+function strings.collapsecrlf(str)
+    return lpegmatch(pattern,str)
+end
+
+--~ local t = {
+--~     "1234567123456712345671234567",
+--~     "a\tb\tc",
+--~     "aa\tbb\tcc",
+--~     "aaa\tbbb\tccc",
+--~     "aaaa\tbbbb\tcccc",
+--~     "aaaaa\tbbbbb\tccccc",
+--~     "aaaaaa\tbbbbbb\tcccccc",
+--~ }
+--~ for k,v do
+--~     print(string.tabtospace(t[k]))
+--~ end
+
+-- The following functions might end up in another namespace.
+
+function strings.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
+
+--~ local template = string.striplong([[
+--~   aaaa
+--~   bb
+--~   cccccc
+--~ ]])
+
+function strings.striplong(str) -- strips all leading spaces
+    str = gsub(str,"^%s*","")
+    str = gsub(str,"[\n\r]+ *","\n")
+    return str
+end