simplify/implizit variable assignment in robotframework -

consider following robotframework code example:

*** variables *** ${var_1}          value ${var_2}          value  *** test cases *** example     ${var_1}=    conversion    ${var_1}     ${var_2}=    conversion    ${var_2}     user keyword    ${var_1}    ${var_2}  desired notation     user keyword    conversion    ${var_1}    conversion    ${var_2}  *** keywords *** conversion     [arguments]    ${value_to_convert}     ${value_to_convert}=    catenate    ${value_to_convert}    foobar     [return]    ${value_to_convert}  user keyword     [arguments]    ${arg1}    ${arg2}     log    ${arg1}     log    ${arg2} 

question: there possibility simplify working testcase for example only (non working) desired notation - or - can somehow use return value of keyword passed parameter without doing explicit assignment before?

for clarification:

• some conversion far more complex , implemented within jrobotremotelibrary
• moving assingments a user keyword no useful solution, because there many keywords different amount of parameters using same functionality

yes, possible. can write own keywords call other keywords passed in arguments

it this:

*** keywords *** user keyword     [arguments]  ${keyword1}  ${var1}  ${keyword2}  ${var2}     ${var1}=  run keyword  ${keyword1}  ${var1}     ${var2}=  run keyword  ${keyword2}  ${var2}     log  ${var1}     log  ${var2} 

you use keyword in example:

a user keyword  conversion  ${var_1}  conversion  ${var_2}