write
+ + + + ] show 2drop ; + +: read-number ( -- ) + [ + +| "Callstack" write |
|---|
| write-eval-link |
| [ unparse write ] with-string-stream write-eval-link |
| "Source" write | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| [ see ] with-simple-html-output | |||||||||
| [ [ parse ] [ [ "No such word" write ] [ car see ] ifte ] catch ] with-simple-html-output | |||||||||
| "Apropos" write | "Usages" write | ||||||||
| [ apropos. ] with-simple-html-output | [ usages. ] with-simple-html-output | @@ -169,10 +171,18 @@ USE: words "eval" get ] bind ; +: infra ( list quot -- list ) + #! Call the quotation using 'list' as the datastack + #! return the result datastack as a list. + datastack >r + swap list>vector tuck vector-push + set-datastack call datastack vector>list + r> >pop> >pop> tuck vector-push set-datastack ; + : do-eval ( list string -- list ) #! Evaluate the expression in 'string' using 'list' as #! the datastack. Return the resulting stack as a list. - parse unit append restack call unstack ; + parse infra ; : do-eval-to-string ( list string -- list string ) #! Evaluate expression using 'list' as the current callstack. @@ -202,8 +212,9 @@ USE: words [ run-eval-requester ] [ - show-message-page + dup [ show-message-page ] [ drop ] ifte ] catch ] forever ; "eval" [ [ ] "None" [ ]||||||||
| "Total Memory" write | +room unparse write | +
| "Free Memory" write | +unparse write | +
| "Total Memory" write | +unparse write | +
| "Free Memory" write | +unparse write | +
"Page 1" write
+ + + + ] show drop + [ + +"Page 2" write
+ + + + ] show drop + [ + drop + +"Page 3" write
+ + + ] show drop ; + + "flowexample1" [ flow-example1 ] install-cont-responder + +The 'flow-example1' word contains three 'show' calls in a row. The +first two display simple pages with an anchor link to the URL received +on the stack. This URL when accessed resumes the computation. The +final page just drops the URL. + +When you display this example in the browser you'll be able to click +the URL to navigate. You can use the back button to retry the URL's, +you can clone the browser window and navigate them independantly, etc. + +The similarity of the functions above could so with some +refactoring. The pages are almost exactly the same so we seperate this +into a seperate word: + + : show-flow-page ( n bool -- ) + #! Show a page in the flow, using 'n' as the page number + #! to display. If 'bool' is true display a link to the + #! next page. + [ ( n bool url -- ) + +"Page " write rot unparse write
+ swap [ + + ] [ + drop + ] ifte + + + ] show 3drop ; + + : flow-example2 ( n -- ) + #! Display the given number of pages in a row. + dup pred [ succ t show-flow-page ] times* + f show-flow-page ; + + "flowexample2" [ 5 flow-example2 ] install-cont-responder + +In this example the 'show-flow-age' pulls the page number off the +stack. It also gets whether or not to display the link to the next +page. + +Notice that after the show that a '3drop' is done whereas +previously we've only done a single 'drop'. This is due to a side +effect or 'show' using continuations. + +After the 'show' call returns there will be one item on the stack +(which we've been dropping and will explain later what it is). The +stack will also be set as it was before the show call. So in this case +the 'n' and 'bool' remain on the stack even though they were removed +during the page generation quotation. This is because we resumed the +continuation which, when captured, had those items on the stack. The +general rule of thumb is you will need to account for items on the +stack before the show call. + +This example also demonstrates using the 'times*' combinator to +sequence the page shows. Any Factor code can be called and the +continuation based system will sequentially display each page. The +back button, browser window cloning, etc will all continue to work. + +You'll notice the URL's in the browser have a number at the end of +them. This is the 'continuation identifier' which is like a session id +except that it identifies not just the data you have stored but your +location within the responder as well. + +Forms and POST data +=================== +The web pages we've generated so far don't accept input from the +user. I've mentioned previously that 'show' returns a value on the +stack and we've been dropping it in our examples. + +The value returned is a namespace containing the field names and +values of any POST data in the request. If no POST data exists then it +is the boolean value 'f'. + +To process input from the user just put a form in the HTML with a +method of 'POST' and an action set to the URL passed in to the page +generation quotation. The show call will then return a namespace +containing this data. Here is a simple example: + + : accept-users-name ( -- name ) + #! Display an HTML requesting the users name. Push + #! the name the user input on the stack.. + [ + +accept-users-name write ", Good to see you!" write
+ + + ] show drop ; + + "post-example1" [ post-example1 ] install-cont-responder + +The 'accept-users-name' word displays an HTML form allowing input of +the name. When that form is submitted the namespace containing the +data is returned by 'show'. We bind to it and retrieve the 'username' +field. The name used here should be the same name used when creating +the field in the HTML. + +'post-example1' then does something a bit tricky. Instead of first +calling 'accept-users-name' to push the name on the stack and then +displaying the resulting page we call 'accept-users-name' from within +the page itself when we actually need it. The magic of the +continuation system causes the 'accept-users-name' to be called when +needed displaying that page first. It is certainly possible to do it +the other way though: + + : post-example2 ( -- ) + accept-users-name + [ ( name url -- ) + drop + +write ", Good to see you!" write
+ + + ] show 2drop ; + + "post-example2" [ post-example2 ] install-cont-responder + +Either way works. Notice that in the 'post-example2' we had to do a +'2drop' instead of a 'drop' at the end of the show to remove the +additional 'name' that is on the stack. This wasn't needed in +'post-example1' because the 'name' was not on the stack at the time of +the 'show' call. \ No newline at end of file diff --git a/contrib/parser-combinators/parser-combinators.factor b/contrib/parser-combinators/parser-combinators.factor index edb9c8b015..a1850fe01c 100644 --- a/contrib/parser-combinators/parser-combinators.factor +++ b/contrib/parser-combinators/parser-combinators.factor @@ -45,7 +45,7 @@ USE: parser #! For a string this is everything but the first character. #! For a list this is the cdr. [ - [ string? ] [ 1 str-tail ] + [ string? ] [ 1 swap str-tail ] [ list? ] [ cdr ] ] cond ; @@ -77,7 +77,7 @@ USE: parser dup str-length pick < [ 2drop "" ] [ - swap str-head + str-head ] ifte ; : (list-take) ( n list accum -- list ) @@ -107,7 +107,7 @@ USE: parser dup str-length pick < [ 2drop "" ] [ - swap str-tail + str-tail ] ifte ; : list-drop ( n list -- list )