diff options
| -rw-r--r-- | share/txr/stdlib/build.tl | 15 | ||||
| -rw-r--r-- | txr.1 | 31 |
2 files changed, 31 insertions, 15 deletions
diff --git a/share/txr/stdlib/build.tl b/share/txr/stdlib/build.tl index 7f0d91c9..1b27d17b 100644 --- a/share/txr/stdlib/build.tl +++ b/share/txr/stdlib/build.tl @@ -37,12 +37,12 @@ (let ((tl (last st))) (usr:rplacd tl (append (cdr tl) items)) (set self.tail tl))) - nil) + self) (:method add* (self . items) (let ((h self.head)) (usr:rplacd h (append items (cdr h)))) - nil) + self) (:method pend (self . lists) (when lists @@ -53,14 +53,14 @@ (nl [apply append lists])) (usr:rplacd tl (append (cdr tl) (if cp (copy-list nl) nl))) (set self.tail tl))) - nil)) + self)) (:method pend* (self . lists) (let* ((h self.head) (pf [apply append (append lists (list (cdr h)))])) (usr:rplacd h pf) (set self.tail h)) - nil) + self) (:method ncon (self . lists) (when lists @@ -68,7 +68,7 @@ (nl [apply nconc lists])) (usr:rplacd tl (nconc (cdr tl) nl)) (set self.tail tl)) - nil)) + self)) (:method ncon* (self . lists) (let* ((h self.head) @@ -76,7 +76,7 @@ (usr:rplacd h pf) (if (eq self.tail h) (set self.tail pf))) - nil) + self) (:method get (self) (cdr self.head)) @@ -113,7 +113,8 @@ (nconc (collect-each ((op '(add add* pend pend* ncon ncon*))) ^(,op (. args) - (qref ,lb-form (,op . args)))) + (qref ,lb-form (,op . args)) + nil)) ^((get () (qref ,lb-form (get))) (del* () @@ -34678,6 +34678,16 @@ method, which is also how the final version of the list is eventually retrieved. The +.code list-builder +methods which add material to the list all return the list builder, +making chaining possible. + +.verb + (new list-builder).(add 1).(add 2).(pend '(3 4 5)).(get) + -> (1 2 3 4 5) +.brev + +The .code build macro is provided which syntactically streamlines the process. It implicitly creates a @@ -34768,8 +34778,9 @@ whereas .code add* adds elements at the front. -These methods return -.codn nil . +These methods return the +.meta list-builder +object. The precise semantics is as follows. All of the @@ -34841,8 +34852,9 @@ however, they avoid mutating those parts of the current list that are shared with inputs that were given in earlier calls to these functions. -These methods return -.codn nil . +These methods return the +.meta list-builder +object. .TP* Example: @@ -34908,8 +34920,9 @@ installed as the terminating atom of the list being constructed, if the current list is an ordinary list. -These methods return -.codn nil . +These methods return the +.meta list-builder +object. .TP* Example: @@ -35031,9 +35044,11 @@ and .codn del* , the local functions return .codn nil , -like the same-named +unlike like the same-named .code list-builder -methods. +methods, which return the +.code list-builder +object. In this lexical environment, each .meta form |