diff options
| -rw-r--r-- | ChangeLog | 23 | ||||
| -rw-r--r-- | eval.c | 42 | ||||
| -rw-r--r-- | lib.c | 2 | ||||
| -rw-r--r-- | txr.1 | 52 |
4 files changed, 96 insertions, 23 deletions
@@ -1,5 +1,28 @@ 2013-10-06 Kaz Kylheku <kaz@kylheku.com> + Improving behavior of op and fixing a bug. + + Explicitly specifying @rest using (op ... . @rest) + did not work at all. + + The then-func agument of iff and iffi may now be nil. + + * eval.c (format_op_arg): New static function. + (transform_op): Handle dotted lists ending in @rest + or @<num>. + (supplement_op_syms): New static function. + (expand_op): Add missing numeric arguments, + so that all 1 through n are in the list. + Trailing rest is now added under different + conditions. + + * lib.c (do_iff): Give thenfun the same + behavior on nil that elsefun enjoys. + + * txr.1: Updated. + +2013-10-06 Kaz Kylheku <kaz@kylheku.com> + New feature: :vars argument in repeat and rep directives in an output block, for specifying variables to include in iteration whose presence repeat is not able to deduce. @@ -1493,6 +1493,11 @@ static val expand_delay(val args) cons(lambda_s, cons(nil, args)), nao); } +static val format_op_arg(val num) +{ + return format(nil, lit("arg-~,02s-"), num, nao); +} + static val transform_op(val forms, val syms, val rg) { if (atom(forms)) { @@ -1501,15 +1506,19 @@ static val transform_op(val forms, val syms, val rg) val fi = first(forms); val re = rest(forms); + if (fi == var_s) { + cons_bind (outsyms, outforms, transform_op(cons(forms, nil), syms, rg)); + return cons(outsyms, rlcp(car(outforms), outforms)); + } + if (consp(fi) && car(fi) == var_s && consp(cdr(fi))) { val vararg = car(cdr(fi)); if (integerp(vararg)) { - val prefix = format(nil, lit("arg-~,02s-"), vararg, nao); val newsyms = syms; val new_p; val *place = acons_new_l(vararg, &new_p, &newsyms); - val sym = if3(new_p, set(*place, gensym(prefix)), *place); + val sym = if3(new_p, set(*place, gensym(format_op_arg(vararg))), *place); cons_bind (outsyms, outforms, transform_op(re, newsyms, rg)); return cons(outsyms, rlcp(cons(sym, outforms), outforms)); } else if (eq(vararg, rest_s)) { @@ -1538,6 +1547,25 @@ static val cons_find(val obj, val structure, val test) cons_find(obj, cdr(structure), test)); } +static val supplement_op_syms(val ssyms, val max) +{ + list_collect_decl (outsyms, tl); + val si, ni; + + for (si = ssyms, ni = one; + ssyms; + ni = plus(ni, one), ssyms = cdr(ssyms)) + { + val entry = car(si); + val num = car(entry); + + for (; lt(ni, num); ni = plus(ni, one)) + list_collect(tl, cons(ni, gensym(format_op_arg(ni)))); + list_collect(tl, entry); + } + + return outsyms; +} static val expand_op(val body) { @@ -1551,14 +1579,18 @@ static val expand_op(val body) val has_rest = cons_find(rest_gensym, body_trans, eq_f); if (!eql(max, length(nums)) && !zerop(min)) - eval_error(body, lit("op: missing numeric arguments"), nao); + ssyms = supplement_op_syms(ssyms, max); rlcp(body_trans, body); { + uses_or2; val dwim_body = rlcp(cons(dwim_s, - append2(body_trans, if3(has_rest, nil, - rest_gensym))), + if3(or3(has_rest, + ssyms, + nullp(proper_listp(body_trans))), + body_trans, + append2(body_trans, rest_gensym))), body_trans); return cons(lambda_s, @@ -3375,7 +3375,7 @@ static val do_iff(val env, val args) cons_bind (thenfun, elsefun, choices); return if3(apply(condfun, args, nil), - apply(thenfun, args, nil), + if2(thenfun, apply(thenfun, args, nil)), if2(elsefun, apply(elsefun, args, nil))); } @@ -9609,11 +9609,11 @@ construct is erroneous. .IP @rest The meta-symbol @rest indicates that any trailing arguments to the -function are to be inserted. If the @<num> syntax is not used anywhere, -it means that the function only has trailing arguments. If @1 is used, -it means that the second and subsequent arguments are trailing arguments. -If @rest is not used anywhere, then the rest arguments are automatically -applied to the op form. If @rest appears, then this is suppressed. +function are to be inserted there. If the form does not contain +any @<num> syntax or @<rest> syntax, then @<rest> is implicitly +inserted. What this means is that, for example, since the form (op foo) does +not contain any numeric positional arguments like @1, and does not contain +@rest, it is actually a shorthand for (op foo . @rest). The actions of form may be understood by these examples, which show how op is rewritten to lambda. However, note that the real translator @@ -9624,13 +9624,27 @@ symbols in the program. (op +) -> (lambda rest [+ . rest]) - (op @1 @2) -> (lambda (arg1 arg2 . rest) [arg1 arg2 . rest]) + (op + foo) -> (lambda rest [+ foo . rest]) + + (op @1 @2) -> (lambda (arg1 arg2 . rest) [arg1 arg2]) + + (op @1 . @rest) -> (lambda (arg1 . rest) [arg1 . @rest]) + + (op @1 @rest) -> (lambda (arg1 . rest) [arg1 @rest]) + + (op @1 @2) -> (lambda (arg1 arg2 . rest) [arg1 arg2]) (op foo @1 (@2) (bar @3)) -> (lambda (arg1 arg2 arg3 . rest) - [foo arg1 (arg2) (bar arg3) . rest]) + [foo arg1 (arg2) (bar arg3)]) (op foo @rest @1) -> (lambda (arg1 . rest) [foo rest arg1]) +Note that if argument @<n> appears, it is not necessary +for arguments @1 through @<n-1> to appear. The function +will have n arguments: + + (op @3) -> (lambda (arg1 arg2 arg3 . rest) [arg3]) + .PP .TP @@ -9738,22 +9752,26 @@ The iff function is the functional equivalent of the if operator. It accepts functional arguments and returns a function. The resulting function takes its arguments and applies them to <cond-func>. If -<cond-func> yields true, then the arguments are passed to <then-func,> and the -resulting value is returned. Otherwise if <cond-func> yields a false result, -and there is no <else-func>, then nil is returned. If <cond-func> yields false, -and an <else-func> exists, then the original arguments are passed to -<else-func> and the resulting value is returned. +<cond-func> yields true, then the arguments are passed to <then-func> and the +resulting value is returned. Otherwise the arguments are passed to <else-func> +and the resulting value is returned. + +If <then-func> needs to be called, but is nil, then nil is returned +immediately. Likewise, if <else-func> needs to be calld, but is nil, then nil +is returned. The iffi function differs from iff only in the defaulting behavior with respect -to the <else-func> argument. The following equivalence holds: +to the <else-func> argument. The following equivalences hold: + + (iffi a b c) <--> (iff a b c) - (iffi a b c) <--> (iff a b c) + (iffi a b) <--> (iff a b identity) - (iffi a b) <--> (iff a b identity) + (iffi a b nil) <--> (iff a b identity) The iffi function defaults to the identity function when <else-func> is -omitted, and therefore is useful in situations when one value is to be replaced -with another one when the condition is true, otherwise left alone. +omitted or nil, and therefore is useful in situations when one value is to be +replaced with another one when the condition is true, otherwise left alone. .SH INPUT AND OUTPUT |