[e-lang] Announcing Release Candidate 0.8.33a: experimental extra sweet when-catch syntaxes

[Mark Miller]

At http://www.erights.org/download/0-8-33/index.html

eBrowser and the standard capDesk demo (capDesk, capEdit, the darpaBrowser 
(evil & regular, confined & not) the web server), all still work.

But the when-catch error cases and the new extra-sweetened syntaxes are only 
very lightly tested. Use at your own risk, and *please* let me know of any 
problems.


Here's an example test case. I am unhappy with the size of the expansion. I 
hope to provide a semantically equivalent but smaller & clearer expansion at 
some point.


$ rune
? pragma.enable("easy-return")
? pragma.disable("explicit-result-guard")
? pragma.enable("easy-when")
? pragma.enable("when-sequence")

? def [p1,r1] := Ref.promise()
# value: [<Promise>, <Resolver>]

? interp.setExpand(true)

? def p3 := when (p1) -> (def p2 := (p1 + 3) <- add(1)) -> { println(p2) }
# expansion: def p3 := {
#                Ref.whenResolved(p1, /** when-catch 'done' function */
#                def "__main$1" {
#
#                    /** Invoke as a function */
#                    method run(resolution__15) {
#                        escape __return {
#                            try {
#                                def _ := Ref.fulfillment(resolution__15)
#                                {
#                                    Ref.whenResolved(def p2 := \
# E.send(p1.add(3), "add", __makeList.run(1)), \
#                                       /** when-catch 'done' function */
#                                    def "__main$1$1" {
#
#                                        /** Invoke as a function */
#                                        method run(resolution__11) {
#                                            escape __return {
#                                                try {
#                                                    def _ := \
# Ref.fulfillment(resolution__11)
#                                                    println.run(p2)
#                                                } catch ex__9 {
#                                                    throw.run(ex__9)
#                                                }
#                                                null
#                                            }
#                                        }
#                                    })
#                                }
#                            } catch ex__13 {
#                                throw.run(ex__13)
#                            }
#                            null
#                        }
#                    }
#                })
#            }

# value: <Promise>

? r1.resolve(66)
# expansion: r1.resolve(66)

# stdout: 70

? p3
# expansion: p3

? p3 == null
# expansion: __equalizer.sameEver(p3, null)

# value: true



? interp.setExpand(false)
# expansion: interp.setExpand(false)

? def [p1,r1] := Ref.promise()
# value: [<Promise>, <Resolver>]

? def p3 := when (p1) -> (def p2 := (p1 + 3) <- add(1)) -> { println(p2) }
# value: <Promise>

? r1.smash("foo")
# value: true

***-----------------------***
*** Trace data written to ***
'C:/Documents and Settings/MILLERM1/.e/etrace/etrace.2004-12-21T05_33_58.968Z.txt'
***-----------------------***
? p3
# value: <ref broken by problem: foo>

?


-- 
Text by me above is hereby placed in the public domain

     Cheers,
     --MarkM