Parse the original prompt for cwd and env names

vendor/clink.lua

@@ -18,12 +18,34 @@ dofile(clink_lua_file)
  -- which echo) don't get the ugly '{lamb}' shown.
 ---
 function set_prompt_filter()
+    -- get_cwd() is differently encoded than the clink.prompt.value, so everything other than
+    -- pure ASCII will get garbled. So try to parse the current directory from the original prompt
+    -- and only if that doesn't work, use get_cwd() directly.
+    -- The matching relies on the default prompt which ends in X:\PATH\PATH>
+    -- (no network path possible here!)
+    local old_prompt = clink.prompt.value
+    local cwd = old_prompt:match('.*(.:[^>]*)>')
+    if cwd == nil then cwd = clink.get_cwd() end
+
+    -- environment systems like pythons virtualenv change the PROMPT and usually
+    -- set some variable. But the variables are differently named and we would never
+    -- get them all, so try to parse the env name out of the PROMPT.
+    -- envs are usually put in round or square parentheses and before the old prompt
+    local env = old_prompt:match('.*%(([^%)]+)%).+:')
+    -- also check for square brackets
+    if env == nil then env = old_prompt:match('.*%[([^%]]+)%].+:') end
+
+    -- build our own prompt
     -- orig: $E[1;32;40m$P$S{git}{hg}$S$_$E[1;30;40m{lamb}$S$E[0m
     -- color codes: "\x1b[1;37;40m"
-    cwd = clink.get_cwd()
-    prompt = "\x1b[1;32;40m{cwd} {git}{hg} \n\x1b[1;30;40m{lamb} \x1b[0m"
-    new_value = string.gsub(prompt, "{cwd}", cwd)
-    clink.prompt.value = string.gsub(new_value, "{lamb}", "λ")
+    local cmder_prompt = "\x1b[1;32;40m{cwd} {git}{hg} \n\x1b[1;30;40m{lamb} \x1b[0m"
+    cmder_prompt = string.gsub(cmder_prompt, "{cwd}", cwd)
+    if env == nil then
+        lambda = "λ"
+    else
+        lambda = "("..env..") λ"
+    end
+    clink.prompt.value = string.gsub(cmder_prompt, "{lamb}", lambda)
 end
 
 ---