syntax command

• syntax parses a command line based on standard Stata syntax diagram
• syntax is flexible enough to handle most common syntaxes

  syntax [varlist] [if] [in] [, Level(int $S_level)]

  replaces

  local varlist "opt"
  local if "opt"
  local in "opt"
  local options "Level(int $S_level)"
  parse "`*'"