xu-hao / tranql-haskell

A Haskell Implementation of TranQL

Syntax

<Expr> ::= ( <Expr> )
       |   <Var>
       |   <Expr> <Expr>
       |   RETURN <Expr>
       |   BIND <Expr> <Expr>
       |   FROM <Var> SELECT <Expr> WHERE <Expr>

Static Semantics

Type

<Type> ::= ( <Type> )
       |   <Base>
       |   Prop
       |   { <Field> : <Type>, ..., <Field> : <Type> }
       |   Set <Type>
       |   Rel <Type>
       |   <Type> -> <Type>

Typing Environment

<TEnv> ::= <eps>
       |   <TEnv>, <Var> : <Type>

Judgement

<Judgement> ::= <TEnv> |- <Expr> : <Type>

Typing Rule

G |- t : query    G |- e1 : qselector t    G |- e2 : qprop t
------------------------------------------------------------
G |- SELECT e1 FROM t WHERE e2 : qset t