TABLE OF CONTENTS

::pwtk::isAtomLabel

SYNOPSIS

proc ::pwtk::isAtomLabel {string} {

PURPOSE

Return 1 if string is an atom label accodint to the QE syntax, and 0 otherwise

BEWARE: if string is an atomic number, 0 is returned!

QE-syntax for atomic label: 

      chemical-symbol X (1 or 2 characters, case-insensitive) or
      chemical-symbol plus a number or a letter, Xn (e.g. Fe1) 
      or X_* or X-* (e.g. C1, C_h)


      max total length cannot exceed 3 characters!

SOURCE

    if { [string is double $string] || [string length $string] > 3 } {
        return 0
    }
    if { [atomSymbol $string] ne "X" } {
        return 1
    } else {    
        return 0
    }
}