diff options
Diffstat (limited to 'txr.1')
| -rw-r--r-- | txr.1 | 25 |
1 files changed, 14 insertions, 11 deletions
@@ -27413,7 +27413,7 @@ as the closure body terminates. .coNP Function @ sys:capture-cont .synb -.mets (sys:capture-cont < name << error-report-sym ) +.mets (sys:capture-cont < name <> [ context-form ]) .syne .desc The @@ -27427,13 +27427,15 @@ A block named must be visible; the continuation is delimited by the closest enclosing block of this name. -The -.meta error-report-sym -argument should be a symbol. It is used in the error message if +The optional +.meta context-form +argument should be a compound form. If +.code sys:capture-cont +reports an error, it reports it against this form, +and uses the form's operator symbol as the name of the function which +encountered the error. If the argument is omitted, .code sys:capture-cont -is incorrectly used. The intent is that higher level constructs built -on this function can pass their own name, so the resulting diagnostic -pertains to these constructs, rather than the lower level interface. +uses its own name. The .code sys:capture-cont @@ -27503,16 +27505,17 @@ with named prompts. (defmacro reset (name . body) ^(block ,name ,*body)) - (defun shft-helper (name fun) - (let ((val (sys:capture-cont name 'shft))) + (defun shft-helper (name fun ctx) + (let ((val (sys:capture-cont name ctx))) (if (car val) (call fun (lambda (arg) (call (cdr val) arg))) (cdr val)))) - (defmacro shft (name var . body) + (defmacro shft (:form ctx name var . body) ^(shft-helper ',name - (lambda (,var) (return-from ,name ,*body)))) + (lambda (,var) (return-from ,name ,*body)) + ',ctx)) ;; Usage: (reset foo (* 2 (shft foo k [k 3]) (shft foo l [l 4]))) |