| name | write-simi-scripts |
| description | Write, explain, migrate, and debug Simi scripts. Use when editing .simi files, choosing language constructs or standard modules, or diagnosing Simi parser, analyzer, or runtime behavior. |
| license | MIT |
| compatibility | Requires this Simi repository or an installed simi executable. |
Write Simi Scripts
Start with the authoritative language guide
Read the relevant topic in the language tour before choosing syntax. For static annotations and inference, also consult the erased type-system design. Current examples must not assume roadmap features.
Workflow
- Identify whether the script needs only portable modules or the CLI-only
std/io capability.
- Write a complete
.simi program using current syntax and compact delimiter formatting.
- Prefer expression-valued control flow, structural patterns, and lazy iterator drivers when state evolves.
- Run the script with
simi run FILE; use simi run --inspect FILE when the final value should also be rendered.
- If the script belongs to this repository, add a focused test or independently validated documentation example at the lowest useful layer.
Core contracts
- Runtime typing is dynamic. Optional annotations and aliases are erased and must not change runtime behavior.
if, case, protected do ... catch ... end, standalone do, and function bodies are value-producing lexical blocks.- Postfix
? passes non-nil values through; nil evaluates the nearest lexical block as nil.
- Booleans are strict; there is no truthiness. Use
type(value) == "integer" for runtime category checks.
- Lists are zero-based and mutable. Maps are insertion-ordered, normalize numeric keys, and delete entries assigned
nil.
- Map patterns are closed by default. Add
.. to permit extra fields or ..rest to capture them.
|> inserts the input as the first call argument. ?> skips only that stage for nil. |> tap and ?> tap preserve the incoming value identity.<| appends exactly one trailing argument to a call. <> is strict string concatenation.- Return
nil for expected absence, raise recoverable values, and leave programmer contract violations as hard diagnostics.
- Callable labels document positional parameters; they do not enable named arguments. Optional generic headers use ordinary Simi type bounds.
- Omit a callable raised contract to infer it, use
! E for an upper bound, and use ! never to forbid language raises. Raised-error contracts are erased and do not affect runtime behavior.
Standard modules
list: list primitives, mutation, copy, and slicing.map: map primitives and inspection.iter: lazy single-pass adapters and consumers.number and string: explicit conversions and scalar operations.std/io: opt-in text IO available from the CLI and engines configured with stdio.
The portable list, map, iter, number, string, and bytes values are globals; their canonical std/* paths remain available through require. std/io always requires an opt-in host capability. Immutable bytes use #[] literals, and the bytes prelude supplies inspection, slicing, concatenation, and integer-list conversion. Filesystem/package discovery, serialization, a formatter, a REPL, runtime tuples, and script-visible command-line arguments are not implemented.
Formatting and checks
Use compact forms such as {a = x, b = y} and [a, b, c]. For a multiline pipeline on a binding RHS, break after = and indent the continuation.
cargo build --bin simi
target/debug/simi run path/to/script.simi
target/debug/simi run --inspect path/to/script.simi
For documentation examples, use truthful simi fences and make each example independently complete. Examples intentionally producing a static diagnostic begin with an -- Expected type comment.
