Add GUI skeleton based on gi-gtk-declarative.

README.md

@@ -17,7 +17,7 @@ sudo apt install graphviz
 
 Then build and execute glance:
 ```
-stack build
+stack build :glance-exe
 stack exec glance-exe -- examples/fact.hs images/fact.svg 500
 ```
 To see the command line options run

glance.cabal

@@ -7,7 +7,7 @@ license:             Apache-2.0
 license-file:        LICENSE
 author:              Robbie Gleichman
 maintainer:          rgleichman@gmail.com
-copyright:           2018 Robbie Gleichman
+copyright:           2020 Robbie Gleichman
 category:            Visual Programming
 build-type:          Simple
 -- extra-source-files:
@@ -57,6 +57,24 @@ executable glance-exe
                , SimplifySyntax
                , Constants
 
+executable glance-gui
+  hs-source-dirs: gui
+  main-is: Main.hs
+  ghc-options:         -threaded -rtsopts -with-rtsopts=-N
+                       -Wall
+                       -Wincomplete-record-updates
+                       -Wmissing-export-lists
+                       -Widentities
+                       -Wpartial-fields
+  build-depends:       base
+                     , gi-gtk
+                     , gi-gtk-declarative
+                     , gi-gtk-declarative-app-simple
+                     , text
+                     , pipes
+                     , pipes-extras
+  default-language:    Haskell2010
+
 test-suite glance-test
   type:                exitcode-stdio-1.0
   hs-source-dirs:      test, app

gui/Main.hs

@@ -0,0 +1,4 @@
+module Main (main) where
+
+main :: IO ()
+main = putStrLn "Glance GUI!"

notes.txt

@@ -24,3 +24,8 @@ stack haddock --open <package-name>
 
 To build and run in a loop
 watch -n2 stack build --exec \"glance-exe examples/fact.hs examples/fact.svg 500\"
+
+
+GUI:
+To build the GUI, first install the system dependencies (follow the directions
+here: https://github.com/haskell-gi/haskell-gi#installation)

stack.yaml

@@ -10,6 +10,8 @@ packages:
 # Packages to be pulled from upstream that are not in the resolver (e.g., acme-missiles-0.3)
 extra-deps: [
 "diagrams-graphviz-1.4.1.1"
+, "gi-gtk-declarative-0.6.3"
+, "gi-gtk-declarative-app-simple-0.6.3"
 ]
 
 # Override default flag values for local packages and extra-deps

todo.md

@@ -1,6 +1,9 @@
 # Todo
 
 ## Todo Now
+* Make a GUI. One approach is to render individual icons with diagrams using the
+Cairo or GTK backend. The rendering would be in a separate process so that
+interacting and dragging nodes is not slowed down by rendering.
 * Redesign case icon to avoid non-locality.
 * Move @ pattern circles so that they are on the same side as the variables.
 * Add command line flags for color style, embedding, and whether to draw arrowheads.