From e6802ca7550a08a38890dc0c976f78e5aab10589 Mon Sep 17 00:00:00 2001
From: Adrian Cochrane <adrian@openwork.nz>
Date: Sat, 14 Nov 2020 15:32:37 +1300
Subject: [PATCH] Add support for range types to media query interpretor.

This allows browsers to be more vague when fetching @imports.
---
 src/Data/CSS/Preprocessor/Conditions/Expr.hs | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/src/Data/CSS/Preprocessor/Conditions/Expr.hs b/src/Data/CSS/Preprocessor/Conditions/Expr.hs
index 99dd7ad..c39d961 100644
--- a/src/Data/CSS/Preprocessor/Conditions/Expr.hs
+++ b/src/Data/CSS/Preprocessor/Conditions/Expr.hs
@@ -72,7 +72,7 @@ pushOp toks op b ops = parse' toks ((op, b):ops)
 ---- Shunting Yard Evaluator
 --------
 -- | Dynamic types for evaluating media queries.
-data Datum = B Bool | N Float | Ratio Float Float deriving Eq
+data Datum = B Bool | N Float | R {minv :: Float, maxv :: Float} | Ratio Float Float deriving Eq
 
 -- | Evaluates a media query with the given functions for evaluating vars & tokens.
 eval :: (Text -> Datum) -> (Token -> Datum) -> Expr -> Bool
@@ -89,10 +89,24 @@ eval' stack v t (Tok (Ident name):ops) = eval' (v name:stack) v t ops
 -- TODO: How should I handle ratios?
 eval' (N y:N x:stack) v t (MkRatio:ops) = eval' (Ratio x y:stack) v t ops
 eval' (N y:N x:stack) v t (Less:ops) = eval' (B (x < y):stack) v t ops
+eval' (R _ y:N x:stack) v t (Less:ops) = eval' (B (x < y):stack) v t ops
+eval' (N y: R x _:stack) v t (Less:ops) = eval' (B (x < y):stack) v t ops
+eval' (R _ y:R x _:stack) v t (Less:ops) = eval' (B (x < y):stack) v t ops
 eval' (N y:N x:stack) v t (LessEq:ops) = eval' (B (x <= y):stack) v t ops
+eval' (R _ y:N x:stack) v t (LessEq:ops) = eval' (B (x <= y):stack) v t ops
+eval' (N y: R x _:stack) v t (LessEq:ops) = eval' (B (x <= y):stack) v t ops
+eval' (R _ y:R x _:stack) v t (LessEq:ops) = eval' (B (x <= y):stack) v t ops
+eval' (R yMin yMax:R xMin xMax:stack) v t (Equal:ops) =
+    eval' (B (xMax >= yMin && xMin <= yMax) : stack) v t ops
 eval' (y:x:stack) v t (Equal:ops) = eval' (B (x == y):stack) v t ops
 eval' (N y:N x:stack) v t (Greater:ops) = eval' (B (x > y):stack) v t ops
+eval' (R y _:N x:stack) v t (Greater:ops) = eval' (B (x > y):stack) v t ops
+eval' (N y:R _ x:stack) v t (Greater:ops) = eval' (B (x > y):stack) v t ops
+eval' (R y _:R _ x:stack) v t (Greater:ops) = eval' (B (x > y):stack) v t ops
 eval' (N y:N x:stack) v t (GreaterEq:ops) = eval' (B (x >= y):stack) v t ops
+eval' (R y _:N x:stack) v t (GreaterEq:ops) = eval' (B (x >= y):stack) v t ops
+eval' (N y:R _ x:stack) v t (GreaterEq:ops) = eval' (B (x >= y):stack) v t ops
+eval' (R y _:R _ x:stack) v t (GreaterEq:ops) = eval' (B (x >= y):stack) v t ops
 eval' (B ret:_) _ _ [] = ret
 eval' [] _ _ [] = True -- Special case
 eval' _ _ _ _ = False -- Error handling fallback.
-- 
2.30.2