Add a way to print the rules as LaTeX

src/Bergamot/Latex.elm

@@ -0,0 +1,34 @@
+module Bergamot.Latex exposing (..)
+
+import Bergamot.Syntax exposing (..)
+import Bergamot.Rules exposing (..)
+
+termToLatex : (a -> String) -> Term a -> String
+termToLatex f t =
+    case t of
+        Call "type" [t1, t2] -> termToLatex f t1 ++ " : " ++ termToLatex f t2
+        Call "intlit" [t1]   -> termToLatex f t1
+        Call "tpair" [t1, t2] -> termToLatex f t1 ++ "\\times" ++ termToLatex f t2
+        Call "plus" [t1, t2] -> termToLatex f t1 ++ " + " ++ termToLatex f t2
+        Call "pair" [t1, t2] -> "(" ++ termToLatex f t1 ++ ", " ++ termToLatex f t2 ++ ")"
+        Call s [] -> "\\text{" ++ s ++ "}"
+        Call s ts -> "\\text{" ++ s ++ "}(" ++ String.join "," (List.map (termToLatex f) ts) ++ ")"
+        Var x -> f x
+        IntLit i -> String.fromInt i
+        StringLit s -> "\"" ++ s ++ "\""
+
+metavariableToLatex : Metavariable -> String
+metavariableToLatex (MkMetavariable s) =
+    let
+        noQuestion = String.dropLeft 1 s
+    in
+        if String.startsWith "tau" noQuestion then "\\" ++ noQuestion else noQuestion
+
+ruleToLatex : Rule -> String
+ruleToLatex r = "\\cfrac{" ++ String.join "\\quad " (List.map (termToLatex metavariableToLatex) r.premises) ++ "}{" ++ termToLatex metavariableToLatex r.conclusion ++ "}\\ \\texttt{" ++ r.name ++ "}"
+
+unificationVarToLatex : UnificationVar -> String
+unificationVarToLatex (MkUnificationVar s) = s
+
+proofTreeToLatex : ProofTree -> String
+proofTreeToLatex (MkProofTree node) = "\\cfrac{" ++ String.join "\\quad " (List.map proofTreeToLatex node.premises) ++ "}{" ++ termToLatex unificationVarToLatex node.conclusion ++ "}\\ \\texttt{" ++ node.name ++ "}"