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mirror of https://codeberg.org/setop/elm-scripting synced 2025-11-08 21:49:57 +00:00

more exploration

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2025-09-27 18:10:33 +02:00
parent 7025bc1104
commit 9566f305b5
6 changed files with 22 additions and 6 deletions

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@@ -8,13 +8,14 @@ A tool to generate HTML code from Elm source in the terminal using [QuickJS](htt
* do not patch elm compiler output
* provide acceptable performances (500ms for a big script)
# Design
QuickJS (Qjs) is a [JavaScript runtime](https://en.wikipedia.org/wiki/List_of_JavaScript_engines), similar to V8 or SpiderMonkey, but lighter and faster.
As any runtime, Qjs can interpret JavaScript code, but it is not a web browser. It has no concept of an HTML document.
To bridge this gap, we add a minimal [DOM](https://developer.mozilla.org/en-US/docs/Web/API/Document_Object_Model) implementation.
To bridge this gap, we add a minimal [DOM](https://dom.spec.whatwg.org/) implementation.
Next, we concatenate this with the Elm JavaScript output and an app launcher snippet, then ask Qjs to interpret all of it.
@@ -24,6 +25,8 @@ Next, we concatenate this with the Elm JavaScript output and an app launcher sni
* Hence, no [TEA](https://guide.elm-lang.org/architecture/); the `main` function must return a static view
* Hence, no Time, no Random, no Json Encoder/Decoder (!), no Http
* Nodes can only have one parent (this should always be the case)
* Does not scale well : creating thousands of Nodes consumes a [lot of RAM](#Performances)
# Usage
@@ -51,6 +54,7 @@ Hello World!
Acceptable for small scripts : 250ms on a modest x86_64 CPU and 64MB RAM for a 500 records into a table ; but is does not scale well as everything is loaded before processing ; no streaming contrary to the usual Unix way.
Generate 500k "li" loop took 17s and 900MB RAM.
# Prior Work

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@@ -6,8 +6,16 @@
- [ ] from files (use case : SSG)
- [ ] from http (use case : spider)
- implements some missing Web API:
- [Events](https://dom.spec.whatwg.org/#events)
- [Fetch](https://fetch.spec.whatwg.org/)(or [XMLHttpRequest](https://xhr.spec.whatwg.org/))
- [Promise](https://webidl.spec.whatwg.org/#a-new-promise) (if needed by the above)
- [ ] find a way to create a standalone executable (maybe with a combination of Google Closure Compiler and qjsc)
- [ ] find a way to stream instead of having the whole document in memory (output as soon as a node is created ? a child is added ?)
# Minor
- [ ] support for Elm debug mode (qjs does not implement `console.warn`, only `console.log`)

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@@ -1,12 +1,14 @@
#!/bin/sh -eu
CMDD=$(dirname $(realpath 0))
w1="$(mktemp out_$$_1_XXXX.js)"
elm make --optimize --output=${w1} $1 1>&2
w2="$(mktemp out_$$_XXXX.js)"
cat dom.js ${w1} launch.js > ${w2}
cat ${CMDD}/dom.js ${CMDD}/preelm.js ${w1} ${CMDD}/postelm.js > ${w2}
rm ${w1}

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dom.js
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@@ -52,7 +52,3 @@ document.getElementById = (_id) => { return target}
document.createElement = (tag) => new Node(null, tag);
document.createTextNode = (text) => { t = new Node(null, "#text" ); t.text = text; return t }
try {
// here will come the Elm app code

6
preelm.js Normal file
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@@ -0,0 +1,6 @@
try {
// here will come the Elm app code