Difference between revisions of "pas2js modules"
| Line 73: | Line 73: | ||
== Module export == | == Module export == | ||
| − | Module export | + | Module export is implemented using the existing pascal '''Library''' concept. |
| + | |||
| + | A pas2js library is transpiled into a Javascript module with its own rtl.js and rtl.run. | ||
| + | For example a library exporting a function: | ||
| + | |||
| + | <syntaxhighlight lang=pascal> | ||
| + | library Fish; | ||
| + | procedure Swim(w: word); | ||
| + | begin | ||
| + | end; | ||
| + | exports | ||
| + | Swim; | ||
| + | Swim name 'Move'; | ||
| + | begin | ||
| + | end. | ||
| + | </syntaxhighlight> | ||
| + | |||
| + | Generates the following JavaScript: | ||
| + | |||
| + | <syntaxhighlight lang=javascript> | ||
| + | ...rtl.js and system unit... | ||
| + | rtl.module("library", [], function () { | ||
| + | var $mod = this; | ||
| + | this.Swim = function (w) { | ||
| + | }; | ||
| + | $mod.$main = function () { | ||
| + | }; | ||
| + | }); | ||
| + | rtl.run("library"); | ||
| + | export const Swim = pas.library.Swim; | ||
| + | export const Move = pas.library.Swim; | ||
| + | </syntaxhighlight> | ||
| + | |||
| + | HTML: | ||
| + | <syntaxhighlight lang=html> | ||
| + | <!DOCTYPE html> | ||
| + | <html lang="en-US"> | ||
| + | <head> | ||
| + | <meta charset="utf-8"> | ||
| + | <title>Basic Pas2JS library example</title> | ||
| + | <script type="module" src="fish.js"></script> | ||
| + | </head> | ||
| + | <body> | ||
| + | |||
| + | </body> | ||
| + | </html> | ||
| + | </syntaxhighlight> | ||
Revision as of 12:44, 22 February 2022
Module import
pas2js can convert the $linklib directive to a JS import statement:
The following:
{$linklib ./modules/canvas.js canvas}
is converted to
import * as canvas from "./modules/canvas.js";
If the alias is omitted, one is constructed for you:
{$linklib ./modules/some-api.js}
is converted to
import * as some_api from "./modules/some-api.js";
The import statements are always inserted in the main program. This is because modules are like windows libraries: self-contained programs, which only import and export well-defined symbols.
For this reason, a new target "operating system" has been invented: the module. This means that you must compile with target module:
pas2js -Tmodule -Jirtl.js main.pp
The nodejs target will also work, but in the future the 2 targets may diverge.
Demos
The pas2js demos/modules directory contains a series of subdirectories. Each subdirectory has 1 demo. Compile with the command-line as above:
pas2js -Tmodule -Jirtl.js main.pp
Basic
This shows a simple program, no units, that uses the linklib directive to import a javascript module. It uses an external class definition to access the exported symbols from the modules.
Basic-Units
This is the same as the Basic example, but the import definitions are split out in units.
Flat
This shows a simple program, no units, that uses the linklib directive to import a javascript module. It uses only external 'name' definitions to access the exported symbols from the modules; no external class is used.
Flat-Units
This is the same as the flat example, but the import definitions are split out in units.
Module export
Module export is implemented using the existing pascal Library concept.
A pas2js library is transpiled into a Javascript module with its own rtl.js and rtl.run. For example a library exporting a function:
library Fish;
procedure Swim(w: word);
begin
end;
exports
Swim;
Swim name 'Move';
begin
end.
Generates the following JavaScript:
...rtl.js and system unit...
rtl.module("library", [], function () {
var $mod = this;
this.Swim = function (w) {
};
$mod.$main = function () {
};
});
rtl.run("library");
export const Swim = pas.library.Swim;
export const Move = pas.library.Swim;
HTML:
<!DOCTYPE html>
<html lang="en-US">
<head>
<meta charset="utf-8">
<title>Basic Pas2JS library example</title>
<script type="module" src="fish.js"></script>
</head>
<body>
</body>
</html>
