parsing expressions (Flash again)

Oh bother, I'd even thought up a response, but neglected to send it :( The response is, Gabriele Santilli some time ago posted a script called expression-evaluator.r. This fairly small script evaluates expressions and I feel it is similar to what you want to achieve. Might be worth studying for ideas. I include it below (I'm guessing it is ok with Gabriele - i hope anyway :) ). Brett ... REBOL [ Title: "Expression evaluator" Author: "Gabriele Santilli <[giesse--writeme--com]>" Comment: { Evaluates expressions taking usual operator precedence into account. 1. (...) 2. - [negation], ! [factorial] 3. ^ [power] 4. *, / 5. +, - [subtraction] } ] ; A simple iterative implementation; returns 1 for negative ; numbers. FEEL FREE TO IMPROVE THIS! factorial: func [n [integer!] /local res] [ if n < 2 [return 1] res: 1 ; should avoid doing the loop for i = 1... repeat i n [res: res * i] ] expression-parser: make object! [ slash: to-lit-word first [/] expr-val: expr-op: none expression: [ term (expr-val: term-val) any [ ['+ (expr-op: 'add) | '- (expr-op: 'subtract)] term (expr-val: compose [(expr-op) (expr-val) (term-val)]) ] ] term-val: term-op: none term: [ pow (term-val: power-val) any [ ['* (term-op: 'multiply) | slash (term-op: 'divide)] pow (term-val: compose [(term-op) (term-val) (power-val)]) ] ] power-val: none pow: [ unary (power-val: unary-val) opt ['^ unary (power-val: compose [power (power-val) (unary-val)])] ] unary-val: pre-uop: post-uop: none unary: [ (post-uop: pre-uop: []) opt ['- (pre-uop: 'negate)] primary opt ['! (post-uop: 'factorial)] (unary-val: compose [(post-uop) (pre-uop) (prim-val)]) ] prim-val: none ; WARNING: uses recursion for parens. primary: [ set prim-val [number! | word!] | set prim-val paren! (prim-val: translate to-block :prim-val) ] translate: func [expr [block!] /local res recursion] [ ; to allow recursive calling, we need to preserve our state recursion: reduce [ :expr-val :expr-op :term-val :term-op :power-val :unary-val :pre-uop :post-uop :prim-val ] res: if parse expr expression [expr-val] set [ expr-val expr-op term-val term-op power-val unary-val pre-uop post-uop prim-val ] recursion res ] set 'eval func [expr [block!] /translate] [ expr: self/translate expr either translate [expr] [do expr] ] ]

YesWow... Oldes Thank you very much! I am really looking forwards to exploring this. Please keep us posted of any developments [including swf examples you make with your toolkit, also any README/Documentation]. + happy thanksgiving to you [it's family holiday today in USA] ./Jason

do %swf-kruh.r ** Script Error: action-bin has no value ** Where: compile ** Near: clear action-bin parse val actions-rules But replacing: do %make-swf.r with: do %make-swf.r action-bin: make binary! 1000 FLASH !!!!!!!!!!!!!!!!!!!!!!!!!!!! Luis

Matrix record so I'm not sure if I'll continue now. I already have what I wanted to...

other files)

Great work! Thank you for sharing it. Btw, roughly how much time did it take to make the swf compiler? Brett.

hmmm... about week for what's already done, but I was playing with decompiling the Flash files year ago so it's difficult to say how much time it tooks me:-) I've downloaded the MING (the C opensource) and I'm really lucky, that I can do it in Flash. It's so difficult to read it in C... and the compiled (win) library for Apache has >700kB. My script hasn't all tags implemented yet but has 7kB now :-) It's a shame, that we cannot do: compress/method "something" 'zlib It would be really usefull and the code has to be in the Rebol already. PS: the Flash spec. you can find here: http://download.macromedia.com/pub/flash/Flash_File_Format_(SWF)_SDK.zip I've just downloaded it and really hate files generated from M$ office:-(((( I really don't understand, why must small HTML file have more then 300kB !!! Oldes