# `.fmscript` 0.90 grammar reference

Source: <https://fmscript.org/spec.html>

This is a concise working reference to the public 0.90 grammar overview. The
published page is not yet the complete script-step catalogue. When a particular
step or parameter variant is uncertain, use a known-good FileMaker/ai2fm export
or validate it with ai2fm; do not infer syntax from another step.

## Core grammar

- Give a parameterized script step exactly one bracket group containing all of
  its parameters.
- Do not add brackets to a step with no parameters.
- Separate main arguments inside the brackets with a semicolon followed by a
  space. Do not use a comma as the main argument separator.
- Use `# ` for a FileMaker comment step.
- Continue the same multiline comment step with `#>`.
- Use `// ` before a script step to represent a disabled step.
- Preserve `//` and `/* */` comments that occur inside FileMaker calculations.
- Qualify field references with their table occurrence, for example
  `Customers::Name`. Do not emit a bare `::Name` reference.
- Prefix a local variable with one `$` and a global variable with exactly `$$`.
- Keep simple steps on one line.
- Preserve multiline calculations and determine their boundary using the known
  step name, balanced brackets, and continuation structure.

## Representative forms

```text
Show All Records
Set Field [ Customers::Name ; "Ada" ]
Set Variable [ $name ; Value: Customers::Name ]
Perform Script [ Specified:From list; "Normalize Customer"; Parameter: $name ]
```

```text
# Prepare the payload
Set Variable [ $payload ; Value: JSONSetElement (
  "{}" ;
  [ "id" ; Customers::ID ; JSONString ]
) ]
```

The exact parameter labels and internal punctuation belong to the individual
FileMaker step definition. Verify them rather than generalizing from these
representative forms.

## Review checklist

- Use an exact, supported FileMaker step name.
- Give each parameterized step one balanced outer bracket group.
- Keep calculation parentheses and internal brackets balanced.
- Use semicolons for main arguments.
- Fully qualify every field reference.
- Use `$` and `$$` variables correctly.
- Close every structured block with the complete matching FileMaker closing
  step.
- Preserve comment steps, disabled steps, and calculation comments correctly.
- Preserve multiline calculation boundaries.
- Apply the project's formatting, naming, path, and output-only requirements.
- Validate uncertain or version-specific syntax through ai2fm or a known-good
  export before describing the script as round-trip ready.