Agda-2.5.1.2: A dependently typed functional programming language and proof assistant

Agda.Compiler.Epic.FromAgda

Description

Convert from Agda's internal representation to our auxiliary AST.

Synopsis

# Documentation

fromAgda :: Maybe Term -> [(QName, Definition)] -> Compile TCM [Fun] Source #

Convert from Agda's internal representation to our auxiliary AST.

Translate an Agda definition to an Epic function where applicable

Arguments

 :: QName -> Int Number of arguments in the definition -> CompiledClauses -> Compile TCM Fun

Translate from Agda's desugared pattern matching (CompiledClauses) to our AuxAST. This is all done by magic. It uses substTerm to translate the actual terms when the cases have been gone through. The case expressions that we get use de Bruijn indices that change after each case in the following way. Say we have this pattern:

f (X x y) (Y z) = term

Initially, the variables have these indexes:

f 0@(X x y) 1@(Y z) = term

The first case will be on 0, and the variables bound inside the X pattern will replace the outer index, so we get something like this:

f 0 2@(Y z) = case 0 of X 0 1 -> term

Notice how (Y z) now has index 2. Then the second pattern is desugared in the same way:

f 0 2 = case 0 of X 0 1 -> case 2 of Y 2 -> term

This replacement is what is done using the replaceAt function.

CompiledClauses also have default branches for when all branches fail (even inner branches), the catchAllBranch. Epic does not support this, so we have to add the catchAllBranch to each inner case (here we are calling it omniDefault). To avoid code duplication it is first bound by a let expression.

substTerm :: [Var] -> Term -> Compile TCM Expr Source #

Translate the actual Agda terms, with an environment of all the bound variables from patternmatching. Agda terms are in de Bruijn so we just check the new names in the position.

Translate Agda literals to our AUX definition