Lexicon & Literals

This page covers the fundamental tokens and literal types in TypR.

Semicolons

Every top-level instruction ends with ;. The parser tolerates missing semicolons (emitting a SyntaxError::ForgottenSemicolon warning), except for the last expression in a block, which acts as an implicit return value — just like in R.

let x <- 42;        # explicit semicolon
let y <- 42         # tolerated, warning emitted

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Literals

Literal	Syntax	Note
Integer	42, -7	Lang::Integer
Number	3.14, -0.5	a decimal point is required for Number; otherwise it's an Integer
String	"text" or 'text'	single and double quotes are interchangeable; escapes: \" \' \\ \n \t
Boolean	true / TRUE, false / FALSE	both lowercase and uppercase forms accepted
Null	null / NULL	Lang::Null — distinct from NA
Missing	na / NA	Lang::NA — distinct from null

Literal types

Literals can also appear as types (singleton types): 3, 3.14, true, "chat" are valid types, more precise than int/num/bool/char.

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Identifiers

Kind	Convention	Example	Enforcement
Variable	snake_case	my_var	must start with a-z or _
Type	PascalCase	MyType	required for type/opaque/alias declarations
Quoted	backticks	`+`, `weird name`	useful for naming custom operators

The parser explicitly rejects casing mistakes:

• let PascalCase <- ... triggers LetInsteadOfType
• type snake_case <- ... triggers TypeInsteadOfLet

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Comments

# This is a comment

Only # is recognized. There is no // syntax — a .ty file containing // will fail silently (see Known Pitfalls).