1 files changed, 168 insertions, 0 deletions
diff --git a/test/format_string.lua b/test/format_string.lua
new file mode 100644
index 0000000000..777fb652e8
--- /dev/null
+++ b/test/format_string.lua
@@ -0,0 +1,168 @@
+local luaassert = require('luassert')
+
+local M = {}
+
+local SUBTBL = {
+  '\\000',
+  '\\001',
+  '\\002',
+  '\\003',
+  '\\004',
+  '\\005',
+  '\\006',
+  '\\007',
+  '\\008',
+  '\\t',
+  '\\n',
+  '\\011',
+  '\\012',
+  '\\r',
+  '\\014',
+  '\\015',
+  '\\016',
+  '\\017',
+  '\\018',
+  '\\019',
+  '\\020',
+  '\\021',
+  '\\022',
+  '\\023',
+  '\\024',
+  '\\025',
+  '\\026',
+  '\\027',
+  '\\028',
+  '\\029',
+  '\\030',
+  '\\031',
+}
+
+--- @param v any
+--- @return string
+local function format_float(v)
+  -- On windows exponent appears to have three digits and not two
+  local ret = ('%.6e'):format(v)
+  local l, f, es, e = ret:match('^(%-?%d)%.(%d+)e([+%-])0*(%d%d+)$')
+  return l .. '.' .. f .. 'e' .. es .. e
+end
+
+-- Formats Lua value `v`.
+--
+-- TODO(justinmk): redundant with vim.inspect() ?
+--
+-- "Nice table formatting similar to screen:snapshot_util()".
+-- Commit: 520c0b91a528
+function M.format_luav(v, indent, opts)
+  opts = opts or {}
+  local linesep = '\n'
+  local next_indent_arg = nil
+  local indent_shift = opts.indent_shift or '  '
+  local next_indent
+  local nl = '\n'
+  if indent == nil then
+    indent = ''
+    linesep = ''
+    next_indent = ''
+    nl = ' '
+  else
+    next_indent_arg = indent .. indent_shift
+    next_indent = indent .. indent_shift
+  end
+  local ret = ''
+  if type(v) == 'string' then
+    if opts.literal_strings then
+      ret = v
+    else
+      local quote = opts.dquote_strings and '"' or "'"
+      ret = quote
+        .. tostring(v)
+          :gsub(opts.dquote_strings and '["\\]' or "['\\]", '\\%0')
+          :gsub('[%z\1-\31]', function(match)
+            return SUBTBL[match:byte() + 1]
+          end)
+        .. quote
+    end
+  elseif type(v) == 'table' then
+    if v == vim.NIL then
+      ret = 'REMOVE_THIS'
+    else
+      local processed_keys = {}
+      ret = '{' .. linesep
+      local non_empty = false
+      local format_luav = M.format_luav
+      for i, subv in ipairs(v) do
+        ret = ('%s%s%s,%s'):format(ret, next_indent, format_luav(subv, next_indent_arg, opts), nl)
+        processed_keys[i] = true
+        non_empty = true
+      end
+      for k, subv in pairs(v) do
+        if not processed_keys[k] then
+          if type(k) == 'string' and k:match('^[a-zA-Z_][a-zA-Z0-9_]*$') then
+            ret = ret .. next_indent .. k .. ' = '
+          else
+            ret = ('%s%s[%s] = '):format(ret, next_indent, format_luav(k, nil, opts))
+          end
+          ret = ret .. format_luav(subv, next_indent_arg, opts) .. ',' .. nl
+          non_empty = true
+        end
+      end
+      if nl == ' ' and non_empty then
+        ret = ret:sub(1, -3)
+      end
+      ret = ret .. indent .. '}'
+    end
+  elseif type(v) == 'number' then
+    if v % 1 == 0 then
+      ret = ('%d'):format(v)
+    else
+      ret = format_float(v)
+    end
+  elseif type(v) == 'nil' then
+    ret = 'nil'
+  elseif type(v) == 'boolean' then
+    ret = (v and 'true' or 'false')
+  else
+    print(type(v))
+    -- Not implemented yet
+    luaassert(false)
+  end
+  return ret
+end
+
+-- Like Python repr(), "{!r}".format(s)
+--
+-- Commit: 520c0b91a528
+function M.format_string(fmt, ...)
+  local i = 0
+  local args = { ... }
+  local function getarg()
+    i = i + 1
+    return args[i]
+  end
+  local ret = fmt:gsub('%%[0-9*]*%.?[0-9*]*[cdEefgGiouXxqsr%%]', function(match)
+    local subfmt = match:gsub('%*', function()
+      return tostring(getarg())
+    end)
+    local arg = nil
+    if subfmt:sub(-1) ~= '%' then
+      arg = getarg()
+    end
+    if subfmt:sub(-1) == 'r' or subfmt:sub(-1) == 'q' then
+      -- %r is like built-in %q, but it is supposed to single-quote strings and
+      -- not double-quote them, and also work not only for strings.
+      -- Builtin %q is replaced here as it gives invalid and inconsistent with
+      -- luajit results for e.g. "\e" on lua: luajit transforms that into `\27`,
+      -- lua leaves as-is.
+      arg = M.format_luav(arg, nil, { dquote_strings = (subfmt:sub(-1) == 'q') })
+      subfmt = subfmt:sub(1, -2) .. 's'
+    end
+    if subfmt == '%e' then
+      return format_float(arg)
+    else
+      return subfmt:format(arg)
+    end
+  end)
+  return ret
+end
+
+return M