| = (assign) | 0.1.0 | 
      
       | . (concat) | 0.1.0 | 
      
       | "{$var}" (variable substitution) | 0.1.0 | 
      
       | .= (assign concat) | 0.1.0 | 
      
       | strval | 0.3.0 | 
      
       | explode/split | 0.3.0 | 
      
       | implode/join | 0.3.0 | 
      
       | sprintf | 0.3.0 | 
      
       | vsprintf | 0.3.0 | 
      
       | trim | 0.4.0 | 
      
       | rtrim | 0.4.0 | 
      
       | ltrim | 0.4.0 | 
      
       | strstr | 0.5.0 | 
      
       | str_pad | 0.5.0 | 
      
       | str_replace | 0.5.0 | 
      
       | substr | 0.5.0 | 
      
       | strtolower | 0.5.0 | 
      
       | strtoupper | 0.5.0 |