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Modules in Sesi

Modules let you split code across .sesi files and reuse it. Use export to expose values from a file and import or allow to bring them in.

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Exporting

Mark any let binding or fn declaration with export to make it available to other files:

// math.sesi
export fn add(a, b) { return a + b }
export fn multiply(a, b) { return a * b }
export let PI = 3.14159

Only exported names are visible to importers. Everything else stays private to the file.

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Importing — `import`

Pull named exports directly into the current scope:

import {
  add,
  multiply,
  PI
} from "math"

print add(10, 20)   // 30
print PI            // 3.14159

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Importing — `allow`

allow is Sesi's scoped import syntax. It has two forms:

Named bindings

Import specific exports directly into scope:

allow "math" in with {
  add, multiply
}

print add(3, 4)   // 7

Namespace object

Import the entire module under a single identifier:

allow "math" in with Math

print Math.add(3, 4)      // 7
print Math.multiply(2, 5) // 10

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Standard Library Modules

Sesi ships with built-in standard library modules:

Module	Namespace	Description
`std/math`	`Math`	Math operations
`std/time`	`Time`	Time/date functions
`std/json`	`JSON`	JSON parsing
`std/db`	—	Database access

allow "std/math" in with Math
allow "std/time" in with Time
allow "std/json" in with JSON

print Math.PI
print Time.now()
print JSON.parse("[1,2,3]")

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Module Resolution Order

When you import "mymodule", Sesi searches for mymodule.sesi in this order:

Priority	Location	Description
1	Script's own directory	Same folder as the running `.sesi` file
2	Current working directory	Where you ran `sesi` from
3	`SESI_PATH`	Colon-separated (Unix) or semicolon-separated (Windows) list of paths
4	`~/.sesi/lib`	Global shared library, available system-wide

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Global Library (`~/.sesi/lib`)

Copy a module to the global library to make it importable from any project on your system:

# macOS / Unix
cp mymodule.sesi ~/.sesi/lib/

# Windows
copy mymodule.sesi $env:USERPROFILE\.sesi\lib\

// Now importable from anywhere
allow "mymodule" in with { helper, util }

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Custom Paths (`SESI_PATH`)

Point SESI_PATH to additional directories for team or monorepo setups:

# macOS / Unix
export SESI_PATH="/mylibs/shared:/projects/common"

# Windows
$env:SESI_PATH = "C:\MyLibs\shared;C:\Projects\common"

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Quick Reference

// Export
export fn greet(name) { print "Hello," name }
export let VERSION = "2.0"

// import (named)
import { greet, VERSION } from "mymodule"

// allow (named bindings)
allow "mymodule" in with { greet, VERSION }

// allow (namespace)
allow "mymodule" in with Mod
Mod.greet("Ada")

// Standard library
allow "std/math" in with Math
allow "std/time" in with Time
allow "std/json" in with JSON

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