beta 2010.12.04 09:44

1 files changed, 59 insertions, 29 deletions

diff --git a/tex/context/base/util-str.lua b/tex/context/base/util-str.lua
index 18caa27bd..adcbf1654 100644
--- a/tex/context/base/util-str.lua
+++ b/tex/context/base/util-str.lua
@@ -10,8 +10,9 @@ 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
+local find, gsub, rep = string.find, string.gsub, string.rep
+local Cs, C, Cp, P, Carg = lpeg.Cs, lpeg.C, lpeg.Cp, lpeg.P, lpeg.Carg
+local patterns, lpegmatch = lpeg.patterns, lpeg.match
 
 -- str = " \n \ntest  \n test\ntest "
 -- print("["..string.gsub(string.collapsecrlf(str),"\n","+").."]")
@@ -30,37 +31,72 @@ function strings.collapsecrlf(str)
     return lpegmatch(pattern,str)
 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 extra, tab, start = 0, 0, 4, 0
+
+local pattern =
+    Carg(1) / function(t)
+        extra, tab, start = 0, t or 7, 1
+    end
+  * Cs((
+      Cp() * patterns.tab / function(position)
+          local current = (position - start + 1) + extra
+          local spaces = tab-(current-1) % tab
+          if spaces > 0 then
+              extra = extra + spaces - 1
+              return rep(" ",spaces)
+          else
+              return ""
+          end
+      end
+    + patterns.newline * Cp() / function(position)
+          extra, start = 0, position
+      end
+    + patterns.anything
+  )^1)
+
+function strings.tabtospace(str,tab)
+    return lpegmatch(pattern,str,1,tab or 7)
+end
+
 --~ local t = {
 --~     "1234567123456712345671234567",
+--~     "\tb\tc",
 --~     "a\tb\tc",
 --~     "aa\tbb\tcc",
 --~     "aaa\tbbb\tccc",
 --~     "aaaa\tbbbb\tcccc",
 --~     "aaaaa\tbbbbb\tccccc",
---~     "aaaaaa\tbbbbbb\tcccccc",
+--~     "aaaaaa\tbbbbbb\tcccccc\n       aaaaaa\tbbbbbb\tcccccc",
+--~     "one\n	two\nxxx	three\nxx	four\nx	five\nsix",
 --~ }
---~ for k,v do
---~     print(string.tabtospace(t[k]))
+--~ for k=1,#t do
+--~     print(strings.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
+function strings.striplong(str) -- strips all leading spaces
+    str = gsub(str,"^%s*","")
+    str = gsub(str,"[\n\r]+ *","\n")
     return str
 end
 
@@ -69,9 +105,3 @@ end
 --~   bb
 --~   cccccc
 --~ ]])
-
-function strings.striplong(str) -- strips all leading spaces
-    str = gsub(str,"^%s*","")
-    str = gsub(str,"[\n\r]+ *","\n")
-    return str
-end