# ==============================================================================
# ModeStringInterpret(default_language): looks for mode strings in the current
#       document, and interprets them.
# ==============================================================================

define ModeStringInterpret
  {
  settings = $empty_array

  if ($n_args >= 1)
    settings["defaultlang"] = $1

  # what sort of mode string do we have?
  vistr = "(?<=(?:^|\\s))vi:\\s*.*"
  emacsstr = "(?<=(?:^|\\s))-\\*-\\s*.*-\\*-"

  pos = 0

  for (beg = search(vistr, 0, "regex"); \
       beg >= 0; \
       beg = search(vistr, pos, "regex"))
    {
    # interpret vi settings
    pos = $search_end
    # dialog("Found vi mode string\n" get_range(beg, pos))
    settings = ModeStringInterpret_vi(get_range(beg, pos), settings)
    }

  for (beg = search(emacsstr, 0, "regex"); \
       beg >= 0; \
       beg = search(emacsstr, pos, "regex"))
    {
    # interpret emacs settings
    pos = $search_end
    # dialog("Found emacs mode string\n" get_range(beg, pos))
    settings = ModeStringInterpret_emacs(get_range(beg, pos), settings)
    }

  if (!("lang" in settings) && ("defaultlang" in settings))
    set_language_mode(settings["defaultlang"])
  }

# ==============================================================================
# ModeStringInterpret_vi(string, settings): augments the editor settings
#       information in settings[] with values taken from string, a "mode line".
#       This is used internally by ModeStringInterpret() for vi-style mode
#       lines.
# ==============================================================================

define ModeStringInterpret_vi
  {
  str = $1
  settings = $2

  # tab settings
  re = ".*:\\s*set\\s+(?:ts|tabstop)\\s*=\\s*(\\d+)\\s*:.*"
  ts = replace_in_string(str, re, "\\1", "regex")
  if (ts != "")
    {
    n = ts
    if ("tab_dist" in settings && n != settings["tab_dist"])
      return ModeStringInterpret_vi_redefinedTabStop()
    else if (0 > n || n > 20)
      return ModeStringInterpret_vi_badTabStopNumber()
    else
      {
      set_em_tab_dist(-1)               # turn off emulated tabs
      set_tab_dist(n)                   # use vi's tab spacing
      set_use_tabs(1)                   # allow use of tabs in auto padding
      settings["tab_dist"] = n
      }
    }

  return settings
  }

# ==============================================================================
# ModeStringInterpret_vi(string, settings): augments the editor settings
#       information in settings[] with values taken from string, a "mode line".
#       This is used internally by ModeStringInterpret() for EMACS-style mode
#       lines.
# ==============================================================================

define ModeStringInterpret_emacs
  {
  str = $1
  settings = $2

  # language mode
  re = ".*(?i[:;-]\\s*(?:(?<!-)mode))\\s*:\\s*([^\\s:;]+).*"
  s = replace_in_string(str, re, "\\1", "regex")
  if (s != "")
    {
    if ("lang" in settings && s != settings["lang"])
      return ModeStringInterpret_emacs_redefinedLanguageMode
    else
      {
      set_language_mode(s)
      settings["lang"] = s
      }
    }

  # tab settings
  re = ".*(?i[:;-]\\s*(?:(?<!-)tab-width))\\s*:\\s*(\\d+).*"
  s = replace_in_string(str, re, "\\1", "regex")
  if (s != "")
    {
    n = s + 0
    if ("tab_dist" in settings && n != settings["tab_dist"])
      return ModeStringInterpret_emacs_redefinedTabStop()
    else if (0 > n || n > 20)
      return ModeStringInterpret_emacs_badTabStopNumber()
    else
      {
      set_em_tab_dist(-1)               # turn off emulated tabs
      set_tab_dist(n)                   # use vi's tab spacing
      set_use_tabs(1)                   # allow use of tabs in auto padding
      settings["tab_dist"] = n
      }
    }

  return settings
  }