LESS CSS concatenate two variables to match one -

im using less dynamically create series of classes. can't seem combine 2 variables match 1 variable have defined.

@import(for.less); 

the pre-defined variables:

@letter-spacing--base: 0; @letter-spacing--xs:   0.2px; 

the loop loops through array:

@classsizes: base, xs; 

the loop creates classes:

.letter-spacing--{     .for(@classsizes); .-each(@value) {          @name: extract(@value, 1);          @valprefix: ~"letter-spacing--";         @valsuffix: @value;          &@{name}{             letter-spacing: ~"@" @valprefix @valsuffix;         }     } } 

this outputs:

.letter-spacing--base {     letter-spacing: @ letter-spacing-- base; } .letter-spacing--xs {     letter-spacing: @ letter-spacing-- xs; } 

it's outputting spaces in between variables doesn't match variables. there way can remove spaces? or maybe there better way of going this.

thanks