General Form (example):

MEAS {DC|AC|TRAN|SP} result TRIG trig_variable VAL=val <TD=td> 
<CROSS=# | CROSS=LAST> <RISE=#|RISE=LAST> <FALL=#|FALL=LAST> 
<TRIG AT=time> TARG targ_variable VAL=val <TD=td>
<CROSS=# | CROSS=LAST> <RISE=#|RISE=LAST>
<FALL=#|FALL=LAST> <TRIG AT=time>

Most of the input forms found in 15.4 may be used here with the command meas instead of .meas(ure). Using meas inside the .control ... .endc section offers additional features compared to the .meas use. meas will print the results as usual, but in addition will store its measurement result (typically the token result given in the command line) in a vector. This vector may be used in following command lines of the script as an input value of another command. For details of the command see Chapt. 15.4. The measurement type SP is only available here, because a fft command will prepare the data for SP measurement. Option autostop (15.1.4) is not available.

Unfortunately par('expression') (15.6.6) will not work here, i.e. inside the .control section. You may use an expression by the let command instead, giving let vec_new = expression.

Replacement for par('expression') in meas inside the .control section

let vdiff = v(n1)-v(n0) 
meas tran vtest find vdiff at=0.04e-3 
*the following will not do here:
*meas tran vtest find par('v(n1)-v(n0)') at=0.04e-3