[gambit-list] (declare (block)) and keyword arguments

Bradley Lucier lucier at math.purdue.edu
Fri Aug 19 17:45:55 EDT 2005


Marc:

I like keyword arguments, and would like to use them more, but they  
are relatively slow for small functions.  So I have a question.

Shouldn't it be possible with (declare (block)) to process keyword  
arguments at compile time rather than by calling ___GET_KEY at run  
time?  Consider the following example:

> (declare (block))
>
> (define (foo #!key bar)
>   bar)
>
> (set! a (foo))
>
> (set! b (foo bar: 2))

This expands to:

> [lindv2:~] lucier% gsc -c -expansion test.scm
> Expansion:
>
> (define foo (lambda (#!key (bar '#f)) bar))
>
> (set! a ((lambda (#!key (bar '#f)) bar)))
>
> (set! b ((lambda (#!key (bar '#f)) bar) bar: 2))

and compiles to:

> #undef ___PH_PROC
> #define ___PH_PROC ___H__20_test
> #undef ___PH_LBL0
> #define ___PH_LBL0 1
> #undef ___PD_ALL
> #define ___PD_ALL ___D_FP ___D_R0 ___D_R1 ___D_R2
> #undef ___PR_ALL
> #define ___PR_ALL ___R_FP ___R_R0 ___R_R1 ___R_R2
> #undef ___PW_ALL
> #define ___PW_ALL ___W_FP ___W_R0 ___W_R1 ___W_R2
> ___BEGIN_P_COD
> ___BEGIN_P_HLBL
> ___DEF_P_HLBL_INTRO
> ___DEF_P_HLBL(___L0__20_test)
> ___DEF_P_HLBL(___L1__20_test)
> ___DEF_P_HLBL(___L2__20_test)
> ___DEF_P_HLBL(___L3__20_test)
> ___DEF_P_HLBL(___L4__20_test)
> ___DEF_P_HLBL(___L5__20_test)
> ___END_P_HLBL
> ___BEGIN_P_SW
> ___DEF_SLBL(0,___L0__20_test)
>    ___IF_NARGS_EQ(0,___NOTHING)
>    ___WRONG_NARGS(0,0,0,0)
> ___DEF_GLBL(___L__20_test)
>    ___SET_STK(1,___R0)
>    ___SET_R0(___LBL(2))
>    ___ADJFP(4)
>    ___POLL(1)
> ___DEF_SLBL(1,___L1__20_test)
>    ___SET_NARGS(0) ___GOTO(___L3__20_test)
> ___DEF_SLBL(2,___L2__20_test)
>    ___SET_GLO(1,___G_a,___R1)
>    ___SET_R2(___FIX(2L))
>    ___SET_R1(___KEY(0,___K_bar))
>    ___SET_R0(___LBL(4))
>    ___SET_NARGS(2) ___GOTO(___L3__20_test)
> ___DEF_SLBL(3,___L3__20_test)
>    ___IF_NARGS_EQ(0,___SET_R1(___FAL))
>    ___GET_KEY(3,0,0,1,___SUB(0))
>    ___JUMPPRM(___NOTHING,___R0)
> ___DEF_SLBL(4,___L4__20_test)
>    ___SET_GLO(2,___G_b,___R1)
>    ___SET_R1(___VOID)
>    ___POLL(5)
> ___DEF_SLBL(5,___L5__20_test)
>    ___ADJFP(-4)
>    ___JUMPPRM(___NOTHING,___STK(1))
> ___END_P_SW
> ___END_P_COD

Couldn't it just be

> Expansion:
>
> (define foo (lambda (#!key (bar '#f)) bar))
>
> (set! a #f)
>
> (set! b 2)

Brad



More information about the Gambit-list mailing list