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February 6, 2014

Project Ideas for the Google Summer of Code 2014

Red has been ramping up its recruiting efforts in 2014.  So far in January, we've done very well with our open-source recruitment campaign on StackOverflow.  Now in February, we are throwing our hat into the ring to be a mentoring organization for Google's Summer of Code:


If you haven't heard about Summer of Code, it pairs college students with mentors who represent an open source project.  The students work remotely and are paid a stipend... and they are expected to complete a measurable goal in the 3 months that they have.  There's an opportunity to start getting involved before the summer, and hopefully the students will have a good experience and stay involved after the summer ends!

Though Nenad will be too busy in the new Beijing Red headquarters :-) to mentor, several members of the Red team have stepped up to volunteer if we are selected.  There is of course around-the-clock support in the [Rebol and Red] chat room, but Google needs commitments from specific people to fill out paperwork and reviews.  As the project "admin" Nenad should only have to be consulted if there was a disagreement between the student and the mentor (which would not happen!)  Of course he would be reviewing any pull request, as with any other code submission.

Google says the best project ideas come from students, which sounds like a good idea.  Still, they require a "starter list" of example projects to originate from the potential mentoring organizations.  So here is the one we came up with...

January 27, 2014

Year of the Horse

In a few days is the Chinese New Year, the year of the Horse. This is what you can find online about its meaning:

The spirit of the horse is recognized to be the Chinese people's ethos – making unremitting efforts to improve themselves. It is energetic, bright, warm-hearted, intelligent and able. Ancient people liked to designate an able person as 'Qianli Ma', a horse that covers a thousand li a day (one li equals 500 meters).
Clever combination of 2,0,1,4 numbers and an artistic horse illustration!

The horse empowers men to reach out far places quickly, Red aims at empowering programmers to accomplish more with less efforts. It looks like the Year of the Horse might be a good one for Red to take off.

I have been travelling through Asia since a month now and will be getting back home in a few days. I went to Hong-Kong, Shanghai and Beijing. This is my first time in Asia, and it felt like accomplish a kid's dream, full of exotic names and places. So, it was full of Marco Polo's stories in mind that I came in China...What a contrast! China is so modern that I must confess Europe looks really behind sometimes... China is also full of opportunities for western people, that's not just a saying, I experienced it first hand.

The purpose of my trip was to get information about the Chinese market for programmers and especially mobile programmers, meet with some startups there and IT people there, present Red (and Rebol) to any group of programmers interested in knowing more about it and get feedback from them.

Meeting with Qtxie, one of the most talented Red contributors.

I got much more than that in fact and I was not even expecting it. Thanks to Jerry Tsai who is supporting Red and Rebol since many years, we could meet with some of the key IT people in China and main startups. I had the opportunity to give an interview at CSDN (the largest developer community in China) and even give a teaching to an audience of beginners and non-programmers using Rebol2 and its GUI DSL.


So, not only, I could gather much more information than I expected, but I could also meet with the #1 incubator in China: InnovationWorks (IW).


IW made me an offer for spending 6 months at their offices in Beijing as a EIR (Entrepreneur In Residence) that I accepted. Basically, I will be able to continue coding on Red project while providing some architecture and tech advices to the incubated startups. This will be a great opportunity for me to study deeply the Chinese programmer's market and prepare for proposing some Red-related products or services in China and worldwide. So I will be moving in Beijing in a few months. This move does not change in any way my work on Red, as I will be able to continue working hard during the whole year on pushing Red closer to a production version.

I was able to work a bit during my trip, mainly on GUI support for Android (reusable for other platforms as well), so the next Red release should feature an alpha version of GUI programming support!

Special thank to Tamas Herman who hosted me during my stay at Hong-Kong and provided me with all I needed for working (including delicious Thai food!). :-)

So, let's start riding the Red horse this year! ;-)

November 30, 2013

0.4.1: Introducing Parse


One of the greatest feature of the Rebol language has always been its parsing engine, simply called Parse. It is an amazing piece of design from Carl Sassenrath, that spared all Rebol users for the last 15 years, from the pain of having to use the famously unmaintainable regexps. Now, Parse is also available to Red users, in an enhanced version!

So, in short, what is Parse? It is an embedded DSL (we call them "dialects" in the Rebol world) for parsing input series using grammar rules. The Parse dialect is an enhanced member of the TDPL family. Parse's common usages are for checking, validating, extracting, modifying input data or even implementing embedded and external DSLs.

The parse function call syntax is straightforward:
    parse <input> <rules>  

    <input>: any series value (string, file, block, path, ...)
    <rules>: a block! value with valid Parse dialect content
Here are a few examples, even if you don't know Red and Parse dialect, you can still "get" most of them, unlike regexps.  You can copy/paste them directly into the Red console.

Some simple examples of string or block input validation using grammar rules:
    parse "a plane" [["a" | "the"] space "plane"]
    parse "the car" [["a" | "the"] space ["plane" | "car"]]

    parse "123" ["1" "2" ["4" | "3"]]
    parse "abbccc" ["a" 2 "b" 3 "c"]
    parse "aaabbb" [copy letters some "a" (n: length? letters) n "b"]

    parse [a] ['b | 'a | 'c]
    parse [hello nice world] [3 word!]
    parse [a a a b b b] [copy words some 'a (n: length? words) n 'b]

How to parse an IPv4 address accurately:
    four:     charset "01234"
    half:     charset "012345"
    non-zero: charset "123456789"
    digit:    union non-zero charset "0"

    byte: [
          "25" half
        | "2" four digit
        | "1" digit digit
        | non-zero digit
        | digit
    ]
    ipv4: [byte dot byte dot byte dot byte]

    parse "192.168.10.1" ipv4
    parse "127.0.0.1"    ipv4
    parse "99.1234"      ipv4
    parse "10.12.260.1"  ipv4

    data: {
        ID: 121.34
        Version: 1.2.3-5.6
        Your IP address is: 85.94.114.88.
        NOTE: Your IP Address could be different tomorrow.
    }
    parse data [some [copy value ipv4 | skip]]
    probe value                      ; will ouput: "85.94.114.88"


A crude, but practical email address validator:
    digit:   charset "0123456789"
    letters: charset [#"a" - #"z" #"A" - #"Z"]
    special: charset "-"
    chars:   union union letters special digit
    word:    [some chars]
    host:    [word]
    domain:  [word some [dot word]]
    email:   [host "@" domain]

    parse "john@doe.com" email
    parse "n00b@lost.island.org" email
    parse "h4x0r-l33t@domain.net" email

Validating math expressions in string form (from Rebol/Core manual):
    expr:    [term ["+" | "-"] expr | term]
    term:    [factor ["*" | "/"] term | factor]
    factor:  [primary "**" factor | primary]
    primary: [some digit | "(" expr ")"]
    digit:   charset "0123456789"
    
    parse "1+2*(3-2)/4" expr        ; will return true
    parse "1-(3/)+2" expr           ; will return false

Creating a simple parser for a subset of HTML:
    html: {
        <html>
            <head><title>Test</title></head>
            <body><div><u>Hello</u> <b>World</b></div></body>
        </html>
    }

    ws: charset reduce [space tab cr lf]

    parse html tags: [
        collect [any [
            ws
            | "</" thru ">" break
            | "<" copy name to ">" skip keep (load name) opt tags
            | keep to "<"
        ]]
    ]

    ; will produce the following tree of blocks as output of parse:
     [
         html [
             head [
                 title ["Test"]
             ]
             body [
                 div [
                     u ["Hello"]
                     b ["World"]
                 ]
             ]
         ]
     ]

The Parse dialect

Parse's core principles are:
  • Advance input series by matching grammar rules until top-level rule failure (returning false) or input exhaustion (returning true). (*)
  • Ordered choices (e.g. in ["a" | "ab"] rule, the second one will never succeed).
  • Rules composability (unlimited).
  • Limited backtracking: only input and rules positions are backtracked, other changes remain.
  • Two modes: string-parsing (for example: external DSL) or block-parsing (for example: embedded DSL).
(*) If collect keyword is used in any rule in its simplest form, a block will be returned by parse no matter if the root rule succeeded or not.


The Parse rules can be made from:
  • keyword : a dialect reserved word (see the tables below).
  • word : word will be evaluated and its value used as a rule.
  • word: : set the word to the current input position.
  • :word : resume input at the position referenced by the word.
  • integer value : specify an iterated rule with a fixed number or a range of iterations.
  • value : match the input to a value
  • | : backtrack and match next alternate rule
  • [rules] : a block of sub-rules
  • (expression) : escape the Parse dialect, evaluate a Red expression and return to the Parse dialect.

The following keywords are currently available in Red's Parse implementation. They can be composed together freely.

Matching

ahead rule : look-ahead rule, match the rule, but do not advance input.
end: return success if current input position is at end.
none: always return success (catch-all rule).
not rule: invert the result of the sub-rule.
opt rule: look-ahead rule, optionally match the rule.
quote value: match next value literally (for dialect escaping needs).
skip: advance the input by one element (a character or a value).
thru rule: advance input until rule matches, input is set past the match.
to rule: advance input until rule matches, input is set at head of the match.

Control flow

break: break out of a matching loop, returning success.
if (expr): evaluate the Red expression, if false or none, fail and backtrack.
into rule: switch input to matched series (string or block) and parse it with rule.
fail: force current rule to fail and backtrack.
then: regardless of failure or success of what follows, skip the next alternate rule.
reject: break out of a matching loop, returning failure.

Iteration

any rule: repeat rule zero or more times until failure or if input does not advance.
some rule: repeat rule one or more times until failure or if input does not advance.
while rule: repeat rule zero or more times until failure regardless of input advancing.

Extraction

collect [rule]: return a block of collected values from the matched rule.
collect set word [rule]: collect values from the matched rule, in a block and set the word to it.
collect into word [rule]: collect values from the matched rule and insert them in the block referred by word.
copy word rule: set the word to a copy of the matched input.
keep rule: append a copy of the matched input to the collecting block.
keep (expr): append the last value from the Red expression to the collecting block.
set word rule: set the word to the first value of the matched input.

Modification

insert only value: insert[/only] a value at the current input position and advance input after the value.
remove rule: remove the matched input.

The core principles mention two modes for parsing. This is necessary in Red (as in Rebol) because of the two basic series datatypes we have: string! and block!. The string! datatype is currently an array of Unicode codepoints (Red will support an array of characters in a future version) while the block! datatype is an array of arbitrary Red values (including other blocks).

In practice, this results in some minor differences in Parse dialect usage. For example, it is possible to define arbitrary sets of characters using the new bitset! datatype, which are useful only for string! parsing in order to match with a large number of characters in one time. Here is an example using only bitsets matching and iterators:
    letter: charset [#"a" - #"z"]
    digit:  charset "0123456789"

    parse "hello 123 world" [5 letter space 3 digit space some letter]

The Bitset! datatype

A bitset value is an array of bits that is used to store boolean values. In the context of Parse, bitsets are very useful to represent arbitrary sets of characters across the whole Unicode range, that can be matched against an input character, in a single operation. As bitset! is introduced in this 0.4.1 release, it is worth having an overview of the features supported. Basically, it is on par with Rebol3 bitset! implementation.

In order to create a bitset, you need to provide one or several characters as base specification. They can be provided in different forms: codepoint integer values, char! values, string! values, a range or a group of previous elements. The creation of a new bitset is done using the following syntax:
    make bitset! <spec>

    <spec>: char!, integer!, string! or block!
For example:
    ; create an empty bitset with places at least for 50 bits
    make bitset! 50

    ; create a bitset with bit 65 set
    make bitset! #"A"

    ; create a bitset with bits 104 and 105 set
    make bitset! "hi"

    ; create and set bits using different values representations
    make bitset! [120 "hello" #"A"]

    ; create a bitset using ranges of values
    make bitset! [#"0" - #"9" #"a" - #"z"]
Ranges are defined using two values (char! or integer! allowed) separate by a dash word.

Bitsets are auto-sized to fit the specification value(s) provided. The size is rounded to the upper byte bound.

A shortcut charset function is also provided for practical usage, so you can write:
    charset "ABCDEF"
    charset [120 "hello" #"A"]
    charset [#"0" - #"9" #"a" - #"z"]

For reading and writing single bits, the path notation is the simplest way to go:
    bs: charset [#"a" - #"z"]
    bs/97     ; will return true
    bs/40     ; will return false
    c: #"z"
    bs/:c     ; will return true
    bs/97: false
    bs/97     ; will return false
(Note: bitset indexing is zero-based.)

Additionally, the following actions are supported by bitset! datatype:
pick, poke, find, insert, append, copy, remove, clear, length?, mold, form

See the Rebol3 bitset documentation for more info about usage of these actions.

In order to cope with the wide range of Unicode characters, bits outside of the bitsets are treated as virtual bits, so they can be tested and set without errors, the bitset size will auto-expand according to the needs. But that is still not enough to deal with big ranges, like for example a bitset for all Unicode characters except digits. For such cases, it is possible to define a complemented bitset that represents the complement range of the specified bits. This makes possible to have large bitsets while using only a tiny memory portion.

Complemented bitsets are created the same way as normal bitsets, but they need to start with the not word and always use a block! for their specification:
    ; all characters except digits
    charset [not "0123456789"]

    ; all characters but hexadecimal symbols
    charset [not "ABCDEF" #"0" - #"9"]

    ; all characters except whitespaces
    charset reduce ['not space tab cr lf]

Set operations are also possible, but only union is currently implemented in Red (it is the most used anyway for bitsets). With union, you can merge two bitsets together to form a new one, which is very useful in practice:
    digit: charset "0123456789"
    lower: charset [#"a" - #"z"]
    upper: charset [#"A" - #"Z"]

    letters:  union lower upper
    hexa:     union upper digit
    alphanum: union letters digit

Parse implementation

Parse dialect has been implemented as a FSM which differs from the Rebol3 implementation that relies on recursive function calls. The FSM approach makes possible several interesting features, like the ability to stop the parsing and resume it later, or even serialize the parsing state, send it remotely and reload it to continue the parsing. Such features could now be implemented with minimal efforts.

Red Parse implementation is about 1300 lines of Red/System code, with a significant part of it spent on optimized iteration loops for common cases. About 770 unit tests have been hand-written to cover the basic Parse features.

The current Parse runs as an interpreter, which is fast enough for most use-cases you will have. For cases where maximum performance is required, work has started on a Parse static compiler to soon provide the fastest possible speed to Parse-intensive Red apps. The generated code is pure Red/System code and should be about a magnitude faster on average than the interpreted version. When Red will be self-hosted, a Parse JIT compiler will be provided to deal with the cases that the static compiler cannot process.

As Red gets more features, Parse will continue to be improved to take advantage of them. Among other future improvements, binary! parsing will be added as soon as binary! datatype is available, and stream parsing will be possible when port! datatype will be there.

The Red Parse also exposes a public event-oriented API in form of an optional callback function that can be passed to parse using the /trace refinement.
    parse/trace <input> <rules> <callback>

    <callback> specification:

    func [
        event   [word!]   ; Trace events
        match?  [logic!]  ; Result of last matching operation
        rule    [block!]  ; Current rule at current position
        input   [series!] ; Input series at next position to match
        stack   [block!]  ; Internal parse rules stack
        return: [logic!]  ; TRUE: continue parsing, FALSE: exit
    ]

    Events list:
    - push    : once a rule or block has been pushed on stack
    - pop     : before a rule or block is popped from stack
    - fetch   : before a new rule is fetched
    - match   : after a value matching occurs
    - iterate : after a new iteration pass begins (ANY, SOME, ...)
    - paren   : after a paren expression was evaluated
    - end     : after end of input has been reached
This API will be extended in the future to get more fine-grained events. This API could be used to provide Parse with tracing, stats, debugging, ... Let's see what Red users will come up with! ;-)

A default callback has been implemented for tracing purposes. It can be accessed using the handy parse-trace function wrapper:
    parse-trace <input> <rules>

You can try it with simple parsing rules to see the resulting output.


What about DSL support?

Parse is a powerful tool for implementing DSL parsers (both embedded and externals), thanks to its ability to inline Red expressions directly into the rules, allowing to easily link the DSL syntax with its corresponding semantics. To illustrate that, here is a simple Brainfuck interpreter written using Parse:
    bf: function [prog [string!]][
        size: 30000
        cells: make string! size
        append/dup cells null size

        parse prog [
            some [
                  ">" (cells: next cells)
                | "<" (cells: back cells)
                | "+" (cells/1: cells/1 + 1)
                | "-" (cells/1: cells/1 - 1)
                | "." (prin cells/1)
                | "," (cells/1: first input "")
                | "[" [if (cells/1 = null) thru "]" | none]
                | "]" [
                   pos: if (cells/1 <> null)
                   (pos: find/reverse pos #"[") :pos
                   | none
                  ]
                | skip
            ]
        ]
    ]

    ; This code will print a Hello World! message
    bf {
        ++++++++++[>+++++++>++++++++++>+++>+<<<<-]>++.>+.+++++++..+++.
        >++.<<+++++++++++++++.>.+++.------.--------.>+.>.
    }

    ; This one will print a famous quote
    bf {
        ++++++++[>+>++>+++>++++>+++++>++++++>+++++++>++++++++>
        +++++++++>++++++++++>+++++++++++>++++++++++++>++++++++
        +++++>++++++++++++++>+++++++++++++++>++++++++++++++++<
        <<<<<<<<<<<<<<<-]>>>>>>>>>>>----.++++<<<<<<<<<<<>>>>>>>
        >>>>>>.<<<<<<<<<<<<<>>>>>>>>>>>>>---.+++<<<<<<<<<<<<<>>
        >>>>>>>>>>>>++.--<<<<<<<<<<<<<<>>>>>>>>>>>>>---.+++<<<<
        <<<<<<<<<>>>>.<<<<>>>>>>>>>>>>>+.-<<<<<<<<<<<<<>>>>>>>>
        >>>>>>+++.---<<<<<<<<<<<<<<>>>>.<<<<>>>>>>>>>>>>>>--.++
        <<<<<<<<<<<<<<>>>>>>>>>>>>>>-.+<<<<<<<<<<<<<<>>>>.<<<<>
        >>>>>>>>>>>>>+++.---<<<<<<<<<<<<<<>>>>>>>>>>>>>>.<<<<<<
        <<<<<<<<>>>>>>>>>>>>>>-.+<<<<<<<<<<<<<<>>>>>>>>>>>>>>-.
        +<<<<<<<<<<<<<<>>>>>>>>>>>>>>--.++<<<<<<<<<<<<<<>>>>+.-
        <<<<.
    }
Note: this implementation is limited to one-level of "[...]" nesting to keep it as short as possible. A complete, but a bit more longer and complex implementation using Parse only, is availaible here.

So, such approach works incredibly well for small DSLs. For more sophisticated ones, Parse still works fine, but it might be less helpful as the DSL semantics get more complex. Implementing an interpreter or compiler for a more advanced DSL is not a trivial task for most users. Red will address that in the future by providing a meta-DSL wrapper on top of Parse, exposing a higher-level API to build more sophisticated DSL by abstracting away core parts of an interpreter or compiler. A DSL for building other DSLs is not a crazy idea, it already exists in a very powerful form as the Rascal language for example. What Red will provide, will be just one step in that direction, but nothing as sophisticated (and complex) as Rascal.

Other changes in this release
Just to mention other changes in this release, now that we got rid of the 800 pound gorilla in the room. This release brings a significant number of bug fixes, both for Red and Red/System. Also, thanks to qtxie, the ELF file emitter is now on par with the other ones when producing shared libraries.

Thanks to all the people involved in helping for this big release, including design fixes and improvements, testing, bug reporting and test writing.

Enjoy! :-)

September 27, 2013

0.4.0: Red goes binary!

What's that?!

As we are getting closer to the end of the alpha period, we are now moving to a more convenient way to use and distribute the Red toolchain. So far, you needed to download a Rebol interpreter and the sources from Github separately, and run it using, a bit verbose, command-lines. This is fine for developping Red  with contributors that are interested in the inner workings of the toolchain, but for the end users, the goal has always been to provide a simpler and much more convenient way, like Rebol teached us in the past.

So, from now, you can get Red as a single binary (< 1 MB) from the new Download page. Yes, all of Red toolchain and runtime is packed in that small binary, even the REPL is built-in!

The Red repo landing page has been reworked to show Red usage in binary form, all previous command-line options are present, a new one (-c) has been introduced. Here is a short overview of the main options:

Launch the REPL:
    $ red 
Run a Red script directly (interpreted):
    $ red <script>
Compile a script as executable with default name in working path:
    $ red -c <script>
Compile a script as shared library with default name in working path:
    $ red -dlib <script>
Compile a script as executable with alternative name:
    $ red -o <new> <script>
Compile a script as executable with default name in other folder:
    $ red -o <path/> <script>
Compile a script as executable with new name in other folder:
    $ red  -o <path/new> <script>
Cross-compile to another platform:
    $ red -t Windows <script>
Display a description of all possible options:
    $ red -h
Notice that -c option is implied when -o or -t are used. It is designed to keep command-lines as simple and short as possible.

Moreover, for standalone Red/System programs, the Red binary will be able to compile them directly, no special option needed, they will be recognized automatically.

Thanks very much to Tamás Herman for helping with setting up the build farm and providing the Mac OSX machine, and thanks to the HackJam hackerspace group from Hong-Kong for the hosting!

Other changes

  • In addition to that new binary form, 17 issues have been fixed since the 0.3.3 release about a month ago (not counting regression tickets).
  • The work on objects support is half-done, objects are working fine with advanced semantics on the interpreter (see object branch), now the focus will be to support them at the Red compiler level.

What's next?

As we are moving closer to the beta state, version numbers will increase faster, e.g., once objects will be done, the release will be the 0.5.0, while 0.6.0 will bring full I/O support. Between these major versions, smaller versions should be still possible, this means that the release cycle should accelerate with at least one release each month from now on. So, what you should expect in the next ones?

0.4.x
  • Simple I/O support: (just read, write and exists? on files)
  • PARSE support
  • Pre-compiled runtime (much faster compilation times)
0.5.0
  • Full object support
0.5.x
  • VID-like cross-platform dialect binding to native widgets.
  • Mezzanine functions additions
  • Redbin (accurate Red values serialization in binary format)
  • Full errors management
  • Red-level exceptions handling

Enjoy!


August 11, 2013

0.3.3: Shared libraries and Android!

This new release took a while, first because a lot of work was done since the last release, about 390 new commits were added and 44 issues were fixed over 80 new tickets opened since the last release. But it was also delayed because, a month ago, I was invited at Recode 2013 developer conference to give a talk and present the latest advancements on Red.




I would like to thank again people that donated to cover the costs of my trip, Brian "HostileFork" Dickens and Coginov in the first place, and all the others that have contributed. I have spent a great time in Montréal and met with lot of Red and Rebol coders, it was great to meet you IRL and spend a few days with you guys!

What's new in 0.3.3?

Java bridge

Since this version, Red is now able to interface with a 32-bit Java Virtual Machine through JNI, using a dedicated bridge written in Red, including a very small part in Java. This bridge allows Red programs to instantiate Java objects and call their methods from Red directly at run-time.

Instructions for using this bridge and compiling the hello example are given on this page.

Here are some screenshots of the resulting AWT hello app done with the Red/Java bridge:

Windows / x86

Linux / ARM

Android support

Red/System runs on Android since more than a year, but we were unable to access the Android API....until now. Thanks to the Red/Java bridge, an Android specific bridge has been made, in order to allow Red to call the whole Android API in Java. This is still alpha stuff, but it works really well, allowing you to build true native Android app in Red, without having to touch any Java code!

This is the hello Red/Android app screenshot, called eval, which simply shows a multiline input field where you can type any Red valid code and run it with the [Do] button. The last expression value gets printed below the button.



You can download the APK file (116KB) with the QR code on the right. 

This is a proof of concept. Now that we know that this way works fine, we will continue to improve the bridge and add new layers of abstraction, in order to keep the low-level Java objects hidden as much as possible for the Red coders and replace them with DSLs and Red ports.

In order to build the eval demo app from the sources, just run the build script from a Rebol2 console.


Shared lib generation

Since a year, we were working on bringing shared library generation, now it is available in the main branch. New features were added to support library generation like a way to declare the exported symbols and special callback functions when loading and freeing the library. Here is a simple example of a Red/System library:

    Red/System [
        File: %testlib.reds
    ]

    inc: func [n [integer!] return: [integer!]][n + 1] 

    #export [inc]


You compile such shared library using the new -dlib command-line option:

   >> do/args %rsc.r "-dlib testlib.reds"
The output binary name will have a platform-specifc suffix (.dll, .so or .dylib).

You can then load this shared library from Red or any other programming language having a good enough FFI. For example, from Red/System, it could be done as simply as:

    Red/System [
        File: %loadlib.reds
    ]

    #import [
        "testlib.dll" stdcall [
            inc: "inc" [n [integer!] return: [integer!]]
        ]
    ]

    print inc 123

This will print 124 when run.


Other Red language changes
  • new action: insert
  • new native: bind
  • new mezzanines: system, any-series?, replace, zero?
  • finished interpreter by adding exit and return support.
  • Function keyword now collects counter words from: repeat, foreach, forall.
  • new #call compilation directive to enable calling Red functions from Red/System.
  • paths now support get-words fully
Red/System got also several improvements:
  • PIC support for both x86 and ARM backends
  • Kernel driver compilation support (Windows only for now)
  • improved function! pointer support, now they can be used as struct members.
  • added new function attribute for dynamic calls: custom
  • new compiler directive for exporting symbols: #export
  • a way to manually align the native stack before making system calls: system/stack/align


What's next?

Android is becoming the dominant OS, so we need to have Red support it as best and as soon as possible. This remains a priority, so improved Android bridge and new sample apps will be available in the next releases. At the same time, we still miss some core features in Red, so these are the new features that you can expect in the next releases of Red:
  • object support
  • simple I/O support
  • whole toolchain released as a single binary (encapped)
  • PARSE support
  • VID-like cross-platform dialect binding to native widgets.
  • mezzanines function additions

We are now heading towards the end of the alpha tunnel, if you look well enough, you'll see the light already. ;-)

Enjoy!

March 23, 2013

0.3.2: REPL release

Time has finally come to release the new REPL for Red. A preview version has been pushed last Christmas, since then a lot of work has been done on several fronts (about 310 new commits, excluding merges): interpreter (DO), runtime lexer (LOAD) and console. But before going into details for the REPL, here is an overview of the changes in this new release:

  • New datatypes: routine!, issue!, file!
  • New natives: do, load, reduce, compose, switch, case, stats, platform?, quit
  • New natives: remove
  • New mezzanines functions: ??, empty?
  • 38 issues from previous releases fixed.
  • Unit tests for Red raised to 5602 for a total of 17671 tests (including Red/System ones).
  • Notable improvements:
    • Paren! expressions in paths now supported.
    • Mold output for string! and char! deeply improved, special characters are now correctly escaped.
    • Improved and more accurate support for unset! values processing.
    • Prin and print now reduce their arguments.

Red REPL

This is the biggest part of this new release. The REPL has several components:
  • The interpreter: it is a full Red interpreter supporting all Red language features, except Red/System code. In the current version, though, exit and return are not yet implemented, they need some special low-level support from Red/System, so couldn't make it for this release. The interpreter can be invoked from compiled code using the do native. It has been developped in Red/System and is about 700 LOC long. All Red compiler tests are run against the interpreter too, all are passing except for the unimplemented yet exit and return (6 tests).
  • The runtime lexer: it is the runtime counterpart to the compiler's lexer and, is in charge of loading input string source code into Red and converting it into blocks of values. It can be invoked from compiled code using the load native. The runtime lexer current version only support Latin-1 encoding, a full Unicode lexer will replace it soon (it is a work in progress).
  • The console: it is the visible part of the REPL for most users. The current version is minimal but works on most of supported platforms (including the RaspberryPi). It has limited editing abilities, and history doesn't work on Mac OS X, but it supports a Rebol-like multi-line input mode for blocks and strings. We will provide a much better console in the next release, with a cross-platform abstraction layer that feature-wise, will put all platforms on par.
The interpreter and runtime lexer and now part of Red's standard library, so they are bundled with every compiled Red script. The overhead is about 30KB in the final binary, making it almost unnoticeable. The console is a separate script, that can be compiled easily producing a small standalone binary.

An important feature of the Red interpreter is that it is not only meant for the REPL support, but is actually used by the compiler to solve some code patterns that are too dynamic to be statically analyzed and compiled. Moreover, the interpreter has the ability to call pre-compiled code, so as soon as possible, it can drop back to native code execution. Both compiled and interpreted code are deeply collaborating to provide the most flexible language semantics while ensuring the maximum performances. With the future addition of a JIT-compiler, we will be able to reach the optimal internal architecture.

Red Collaborative Execution Model

On the more practical side, to compile the console, from Red root folder, just do:
do/args %red.r "red/tests/console.red"

That will give you a console binary in the working folder. When you run it, you should see:

-=== Red Console alpha version ===-
(only Latin-1 input supported) 
 
red>> 
This is the Red prompt where you can input any valid Red expression, they will be evaluated on Enter key pressed. Use q or quit to exit the console. Remember that there is no yet proper error management, current error messages are hardcoded, and in some cases, you will be thrown out of the console (that is why it is still an alpha version as stated by the console banner). Note that it is possible to copy/paste Red scripts directly into the console.

Anyway, feel free to experiment.

Routines

In order to more easily interface Red and Red/System, a new function datatype has been added: routine!. A routine is Red/System function defined in a Red program. The routine specification takes Red datatypes as arguments and return value, and the routine will automatically convert them to appropriate Red/System types when called. For example:
increment: routine [
    n       [integer!]
    return: [integer!]
][
    n + 1
]
Here you can see how the Red integer! argument get marshalled forth and back to Red/System integer! datatype for you. For now, routines automatically converts integer! and logic! datatypes this way. Other Red datatypes are passed as their Red/System counterparts as defined in Red's runtime (see %red/runtime/datatypes/structures.reds). Optional arguments are not supported by routines, as such feature does not exist in Red/System for now.

You can now very easily extend Red with routines using the full power of Red/System! Compiled routines can be run from interpreter too.

Project management

We are now moving to Trello for tracking the tasks about Red development. The short-term ToDo list is pretty accurate and updated regularly, you can now follow us more closely. We only started using it a month ago, so not all the tasks (especially the mid-term/long-term ones) are inserted there yet.

Thanks for all the support received for getting this major release out!
Cheers!

January 2, 2013

Fast forwarding Red history

At the beginning of this new year, I took a moment to look at the work we did since the first public commit of Red. Even if I am a perfectionist that is never satisfied with its own work, I must admit we did a quite incredible job so far. In two years we built not one but two programming languages: Red/System which is in beta state and usable to make real world apps, and Red which is in alpha state and evolving at very fast pace. We built two compilers and one interpreter. We replaced the whole gcc toolchain by our own simple one with incredibly small footprint. We run on ARM platforms since a year now and some experimental Red/System code even runs on Arduino boards. If someone told me two years ago that we will accomplish all that, I am not sure I would have believe it.

So in order to celebrate what we have achieved so far, I offer you an animation showing the history of all 1554 public commits of the project (excluding merge commits) in less than 2 minutes:


This video was made using the gource tool and encoded using ffmpeg. This is my first video uploaded to youtube, so I had to lower the original video quality in order for youtube to process it correctly. You can view it in 720p for best quality.

You can see me and Peter WA Wood flying around the project files making changes and addition. Sometimes Andreas Bolka is popping up to give us a hand, usually on pretty complex bug cases or to update  his ELF format emitter.

I would like to take this opportunity to thank all the people that sent me donations since the beginning, that strongly believe in and support Red project. I would like to especially thank the biggest donators:

Nick Antonaccio
Jerry Tsai
Gregg Irwin
Bas de Lange
Petr Krenzelok

I would have never believed that such level of support from a small community of followers was possible. I am amazed and feel extremely grateful to these people and all the other ones that sent me donations or contributed in a way or another to Red. I would also like to mention and thank two direct contributors to Red project: Kaj de Vos, for his involvement in supporting Red and all the bindings he produced for Red/System, Kaj is still the most prolific Red/System coder so far, and Rudolf Meijer for reverse-engineering Red/System and writing the official language specification document.

To all Red followers, I wish you a Happy New Year! Among many other new features, this year will see the extension of Red to mobile world, with full support for Android and iOS. Let's make it the year where Red will rise even higher than we could have thought possible!

Cheers!