New "parser" hierarchy. [Part 6]

1 files changed, 44 insertions, 0 deletions

diff --git a/stdlib/source/parser/lux/world/environment.lux b/stdlib/source/parser/lux/world/environment.lux
new file mode 100644
index 000000000..33089f2a3
--- /dev/null
+++ b/stdlib/source/parser/lux/world/environment.lux
@@ -0,0 +1,44 @@
+(.require
+ [library
+  [lux (.except)
+   [control
+    ["//" parser]
+    ["[0]" try (.only Try)]
+    ["[0]" exception (.only exception)]]
+   [data
+    ["[0]" product]
+    ["[0]" text (.only)
+     ["%" \\format (.only format)]]
+    [collection
+     ["[0]" dictionary (.only Dictionary)]]]]])
+
+(type .public Property
+  Text)
+
+(type .public Environment
+  (Dictionary Property Text))
+
+(exception .public (unknown_property [property Property])
+  (exception.report
+   "Property" (%.text property)))
+
+(type .public (Parser a)
+  (//.Parser Environment a))
+
+(def .public empty
+  Environment
+  (dictionary.empty text.hash))
+
+(def .public (property name)
+  (-> Property (Parser Text))
+  (function (_ environment)
+    (case (dictionary.value name environment)
+      {.#Some value}
+      {try.#Success [environment value]}
+      
+      {.#None}
+      (exception.except ..unknown_property [name]))))
+
+(def .public (result parser environment)
+  (All (_ a) (-> (Parser a) Environment (Try a)))
+  (at try.monad each product.right (parser environment)))