Keywords and Symbols

Tables of keywords and other lexical symbols for the Rel language.

Keyword	Description
`and`	logical conjunction
`as`	introduces a local name for a relation imported from another module
`bound`	begins a bound declaration
`def`	begins the declaration of a relation
`else`	separates the two branches of a conditional expression
`end`	ends a conditional expression or a module
`entity`	begins the declaration of an entity type (deprecated)
`exists`	the existential quantifier
`false`	boolean constant (the empty relation `{}`)
`for`	an alternative form of relational abstraction
`forall`	the universal quantifier
`from`	a variant of inverse relational abstraction
`ic`	begins the declaration of an integrity constraint
`if`	begins a conditional expression
`iff`	boolean equivalence
`implies`	logical implication
`in`	binds a variable to the elements of a set of unary tuples.
`module`	begins the declaration of a module
`not`	logical negation
`or`	logical disjunction
`then`	separates the condition and the first branch of a conditional expression
`true`	boolean constant (the singleton relation `{()}`)
`use`	begins the list of names imported from another module
`where`	binds variables to sets of values that satisfy a formula
`with`	begins the declaration of imports from another module
`xor`	logical “exclusive or”

Symbol	Operator Name
`.`	dot
`,`	comma
`;`	semicolon
`:`	colon
`(`, `)`	parentheses (precedence)
`(`, `)`	parentheses (application)
`{`, `}`	curly braces (precedence)
`{`, `}`	curly braces (definitions)
`[`, `]`	square brackets
`=`	equal (definitions)
`∈`	`in`
`%`	string interpolation in string constants
`#`	specialization

User-defined Symbols
`⊗`, `⊙`, `⊕`, `⊔`, `⊓`, `∼`, `≼`, `≽`, `≺`, `≻`, `→`, `←`, `≈`	infix symbols

Was this doc helpful?