Language.Sally.Expr

Better constructors for Sally expresssions and predicates than the raw ones defined in Language.Sally.Types.

better constructors

boolExpr :: Bool -> SallyExpr

Create a constant boolean expression.

boolPred :: Bool -> SallyPred

Create a constant boolean predicate.

intExpr :: Integral a => a -> SallyExpr

Create a constant integer expression.

zeroExpr :: SallyExpr

Create an expression for zero as an integer in Sally.

oneExpr :: SallyExpr

Create an expression for one as an integer in Sally.

realExpr :: Real a => a -> SallyExpr

Create a constant real expression.

addExpr :: SallyExpr -> SallyExpr -> SallyExpr

Better constructor for adding expressions TODO maintain normal form

subExpr :: SallyExpr -> SallyExpr -> SallyExpr

Subtract two SallyExpr.

multExpr :: SallyExpr -> SallyExpr -> SallyExpr

Better constructor for multiplying expressions; checks that one of the operands is a constant.

divExpr :: SallyExpr -> SallyExpr -> SallyExpr

Better constructor for dividing expressions; checks that the denominator is a constant.

notExpr :: SallyExpr -> SallyExpr

Create the expression that is the boolean negation of the given one.

eqExpr :: SallyExpr -> SallyExpr -> SallyExpr

Create the expression equating two given expressions.

neqExpr :: SallyExpr -> SallyExpr -> SallyExpr

Create the expression representing non-equality.

ltExpr :: SallyExpr -> SallyExpr -> SallyExpr

a `ltExpr` b represents the expression a < b.

leqExpr :: SallyExpr -> SallyExpr -> SallyExpr

a `leqExpr` b represents the expression a <= b.

gtExpr :: SallyExpr -> SallyExpr -> SallyExpr

a `gtExpr` b represents the expression a > b.

geqExpr :: SallyExpr -> SallyExpr -> SallyExpr

a `geqExpr` b represents the expression a >= b.

muxExpr :: SallyExpr -> SallyExpr -> SallyExpr -> SallyExpr

Create an if-then-else expression: mux b x y represents the statement if b then x else y.

andExprs :: [SallyExpr] -> SallyExpr

Form the conjunction of the given expressions (which should be predicates, but this is not checked).

andPreds :: [SallyPred] -> SallyPred

And over multiple predicates, doing some small inline simplification

orExprs :: [SallyExpr] -> SallyExpr

Form the disjunction of the given expressions (which should be predicates, but this is not checked).

varExpr :: SallyVar -> SallyExpr

Create a variable expression.

varExpr' :: Name -> SallyExpr

Create a variable expression from a name.

xorExpr :: SallyExpr -> SallyExpr -> SallyExpr

Create the XOR of two Sally expressions.

complex expression builders

minExpr :: [SallyExpr] -> Maybe SallyExpr -> SallyExpr

Given a non-empty finite list of expressions, build an expression to compute their minimum. The second argument is a special value which, if present causes expressions in the list with this value to be ignored in the calculation. If the input list contains only the special value, then the special value itself is returned.

countExpr :: SallyExpr -> [SallyExpr] -> SallyExpr

Build a Sally expression representing the number of times a particular item appears in a list of expressions.

expression rewriting

constFold :: SallyExpr -> SallyExpr

A basic top-down recursive constant folding function.

simplifyAnds :: SallyPred -> SallyPred

Top-down rewriting of conjunctions of terms including constant folding and constructor reduction.

simplifyOrs :: SallyPred -> SallyPred

Top-down rewriting of disjunctions including constant folding and constructor reduction.

flattenAnds :: Seq SallyPred -> Seq SallyPred

Recursively flatten a tree of and expressions into an and sequence.

flattenOrs :: Seq SallyPred -> Seq SallyPred

Recursively flatten a tree of or expressions into an or sequence.