# Lil Quick Reference

## Types

`typeof` | False | Examples
--- | --- | ---
`"number"` | `0` | `42` `37.5` `-29999`
`"string"` | `""` | `"foo\nbar"`
`"list"` | `()` | `11,22,33` `list 3`
`"dict"` | `()dict()` | `("a","b") dict 11,22`
`"table"` | n/a | `table range 2` `insert a with 1 end`
`"function"` | n/a | `on x y do x+y end`

## Primitives

Valence | Purpose |
--- | --- | ---
monad | arithmetic | `-` `!` `floor` `cos` `sin` `tan` `exp` `ln` `sqrt` `mag` `unit` `heading`
monad | reducers | `count` `first` `last` `sum` `prod` `min` `max` `raze`
monad | data | `range` `keys` `list` (enlist) `rows` `cols` `table` `typeof` `flip`
dyad | arithmetic | `+` `-` `*` `/` `%` (y mod x) `^` (pow) `&` (min) `|` (max)
dyad | logical | `<` `>` `=` (conforming equal) `~` (match) `unless` (x if y is `0`)
dyad | string | `fuse` `split` `parse` `format` `like`
dyad | data | `,` (concat) `@` (index each right) `dict` `take` `drop` `limit` `in`
dyad | joins | `join` (natural join/zip) `cross` (cross join/cartesian product)

## Flow

- `if bool ... end`
- `if bool ... else ... end`
- `if bool ... elseif bool ... else ... end` (etc)
- `each val key index in x ... end`
- `while bool ... end`
- `send name[args]`

## Queries

- `select exprs clauses from y` reorder, compute, or filter a table
- `update exprs clauses from y` modify rows/columns of a table in place
- `extract exprs clauses from y` like select, but yields non-tabular values
- `insert c1 c2 with "A" 11 "B" 22 end` create a new table
- `insert c1 c2 with "A" 11 "B" 22 into d` append to a table

- `exprs` can be any number of expressions in the forms:
  - an implicitly named bare expression (`id`, `2*index`)
  - an explicitly named expression (`ident:id`, `dogyears:7*age`)
  - a quoted name, for invalid identifiers (`"not a lil id":foo`)
  - if no expressions are provided, all columns will be returned, like `select *` in SQL

- `clauses` can be any sequence of the following, evaluated right to left:
  - `by a`: group rows by the unique values of column b
  - `where a`: filter rows by a boolean column a
  - `orderby a asc`/`orderby a desc`: sort rows, comparing values of column a as by `<`/`>`

- special columns/values available when computing any column expression:
  - `index`: magic column of original row numbers
  - `gindex`: magic column of current row number within group (or all rows if ungrouped)
  - `group`: magic column of row's group, by appearance (or `0` if ungrouped)
  - `column`: dictionary of the entire group's columns (or all rows if ungrouped)

## Formatting

A format is `%[name]*-0N.DX`: `*` skip, `0` pad, `N` width.

`-` is invert char class (`ro`) or left justify.

`.D` is decimal places (`fc`), size of char class (`ro`), or truncate to `D` characters.

`X` | Purpose |
--- | --- | ---
`%nmz` | Parsing | literal `%`, number of chars read, matches? matches to end?
`ro` | Matching | repeat (0 or more in char class), optional (0 or 1 in char class)
`sula` | String | string, uppercase string, lowercase string, ASCII chars
`bficChH` | Number | bool, float, int, currency (`-$1.23`), plain currency (`-1.23`), hex lowercase, hex uppercase
`jep` | Misc. | JSON, unix epoch, time-parts {`year`, `month`, `day`, `hour`, `minute`, `second`}
`qv` | Lil | quoted Lil string literal, Lil variable name

Glob patterns for `like`:

- `.`: any single character.
- `#`: any single digit 0-9.
- `*`: 0 or more of any character.
- backtick escapes a subsequent special character.