UrWeb - Programming language

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UrWeb is an open source programming language created in 2008.

#564on PLDB

16Years Old

83Repos

Download source code:

git clone https://github.com/urweb/urweb

Homepage · Source Code

The Ur/Web programming language

Tags: programming language
UrWeb is developed on GitHub and has 806 stars
There are at least 83 UrWeb repos on GitHub
UrWeb is written in Standard ML, Python, C, Lisp, Make, Bourne shell, M4, Coq, JavaScript, Nix, CSS, HTML, Tex, Lex, Markdown, Lua, YAML, SQL
The Google BigQuery Public Dataset GitHub snapshot shows 62 users using UrWeb in 64 repos on GitHub
GitHub supports syntax highlighting for UrWeb

Example from Linguist:

open Parse.String

val digit = satisfy isdigit

val decimal_of_len n =
    ds <- count n digit;
    return (List.foldl (fn d acc => 10*acc + ((ord d)-(ord #"0"))) 0 ds)

val date =
    y <- decimal_of_len 4;
    char' #"-";
    m <- decimal_of_len 2;
    char' #"-";
    d <- decimal_of_len 2;
    if m > 0 && m <= 12 then
        return {Year=y, Month=(Datetime.intToMonth (m-1)), Day=d}
    else
        fail

(* We parse fractions of a second, but ignore them since Datetime
   doesn't permit representing them. *)
val time =
    h <- decimal_of_len 2;
    char' #":";
    m <- decimal_of_len 2;
    s <- maybe (char' #":";
                s <- decimal_of_len 2;
                maybe' (char' #"."; skipWhile isdigit);
                return s);
    return {Hour=h, Minute=m, Second=Option.get 0 s}

val timezone_offset =
    let val zulu = char' #"Z"; return 0
        val digits = decimal_of_len 2
        val sign = or (char' #"+"; return 1)
                      (char' #"-"; return (-1))
    in
        zulu `or` (s <- sign;
                   h <- digits;
                   m <- (maybe' (char' #":"); or digits (return 0));
                   return (s*(h*60+m)))
    end

val datetime_with_tz =
    d <- date; char' #"T"; t <- time;
    tz <- timezone_offset;
    return (d ++ t ++ {TZOffsetMinutes=tz})

val datetime =
    d <- datetime_with_tz;
    return (d -- #TZOffsetMinutes)

fun process v =
    case parse (d <- datetime_with_tz; eof; return d) v of
        Some r =>
        let
            val {Year=year,Month=month,Day=day,
                 Hour=hour,Minute=minute,Second=second} =
                Datetime.addMinutes (r.TZOffsetMinutes) (r -- #TZOffsetMinutes)
            fun pad x =
                if x < 10 then "0" `strcat` show x else show x
        in
            <xml>{[pad hour]}:{[pad minute]}:{[pad second]} {[month]} {[day]}, {[year]}</xml>
        end
      | None => <xml>none</xml>

fun main () : transaction page =
    input <- source "2012-01-01T01:10:42Z";
    return <xml>
      <body>
        <label>
          Enter an
          <a href="https://en.wikipedia.org/wiki/ISO_8601">ISO 8601</a>
          datetime here:
          <ctextbox source={input} />
        </label>
        <ul><dyn signal={v <- signal input; return (process v)} /></ul>
      </body>
    </xml>

Language features

Feature	Supported	Example	Token
Comments	✓	(* A comment *)
MultiLine Comments	✓	(* A comment *)	(* *)
Semantic Indentation	X