Learn about how compilers work and the choices necessary to create a well-defined programming language.
| Representation | Meaning |
|---|---|
| Plain words or symbols | A literal token, representing itself in the exact way it is displayed. |
Words surrounded by angle brackets < > |
A single token of that description is required in that position. |
Words surrounded by squiggly brackets { } |
An optional single instance of the given tokens. One or none. |
Words surrounded by square brackets [ ] |
An optional repeating sequence of the given tokens. Many or none. |
| Kind | Meaning |
|---|---|
| identifier | A word that must start with an upper or lower case character, but after that can also consist of digits and underscore _. An identifier may or may not be defined to have a corresponding value. |
| keyword | A member of an exclusive collection of reserved words that cannot be used as identifiers. They are used by the compiler to enforce an unambiguous grammar and sentence structure. |
| integer | A number that exists entirely of digits 0-9 optionally separated by underscore _. |
| separator | A member of a collection of symbols that are used to separate different expressions from each other in ways defined by the grammar. |
A definition is a type of statement that creates a connection between a given identifier and a value, such that the identifier represents a value.
def <identifier> {of <type>} is <statement>
val <identifier> {of <type>} is <statement>
var <identifier> {of <type>} is <statement>
fun <identifier>({<identifier> of <type> [, <identifier> of <type>]}) to <type> is [<statement>] ret <statement>
pro <identifier>({<identifier> of <type> [, <identifier> of <type>]}) to <type> is [<statement>] ret <statement>
