Merge pull request #1 from emacs-twist/fix-odd-arguments

Fix handling of source blocks with odd arguments

.github/workflows/test.yml

@@ -19,3 +19,5 @@ jobs:
           access-tokens = github.com=${{ secrets.GITHUB_TOKEN }}
     - name: Run tests
       run: nix-instantiate --eval --strict test/test.nix
+    - name: Test parameter parsing
+      run: nix-instantiate --eval --strict test/testParams.nix

nix/parseParamsString.nix

@@ -1,11 +1,36 @@
 with builtins;
 let
+  takeWhile = p: xs:
+    if length xs == 0
+    then [ ]
+    else if p (head xs)
+    then [ (head xs) ] ++ takeWhile p (tail xs)
+    else [ ];
+
+  dropWhile = p: xs:
+    if length xs == 0
+    then [ ]
+    else if p (head xs)
+    then dropWhile p (tail xs)
+    else xs;
+
+  isKeyword = s: stringLength s > 0 && substring 0 1 s == ":";
+
+  notKeyword = s: !(isKeyword s);
+
+  toValue = xs:
+    if length xs == 0
+    then true
+    else if length xs == 1
+    then head xs
+    else xs;
+
   listToAttrs = xs:
     if length xs == 0
     then { }
-    else if length xs == 1
-    then throw "parseParamsString: Found an odd number of items: ${head xs}"
-    else { ${head xs} = elemAt xs 1; } // listToAttrs (tail (tail xs));
+    else {
+      ${head xs} = toValue (takeWhile notKeyword (tail xs));
+    } // listToAttrs (dropWhile notKeyword (tail xs));
 
   stripPat = "[[:space:]]+(.*)";
 
@@ -20,6 +45,10 @@ let
 
   go = m: [ (elemAt m 0) ] ++ parse (elemAt m 1);
 
+  # TODO: Handle expressions
+  #
+  # This will be hard, as it requires an elisp parser.
+  # It is probably better to unsupport it.
   parse' = string:
     if string == ""
     then [ ]

test/testParams.nix

@@ -0,0 +1,42 @@
+# nix-instantiate --eval --strict test/testParams.nix
+let
+  pkgs = import <nixpkgs> {};
+  parse = import ../nix/parseParamsString.nix;
+in
+pkgs.lib.runTests {
+  testSimple = {
+    expr = parse ":tangle no";
+    expected = {
+      ":tangle" = "no";
+    };
+  };
+
+  testOdd = {
+    expr = parse ":async";
+    expected = {
+      ":async" = true;
+    };
+  };
+
+  testNonAlpha = {
+    expr = parse ":session kernel-16577-ssh.json";
+    expected = {
+      ":session" = "kernel-16577-ssh.json";
+    };
+  };
+
+  # This case is unsupported right now.
+  #
+  # testExpression = {
+  #   expr = parse ":value '(this is so annoying)";
+  #   expected = { };
+  # };
+
+  testDoubleQuotes = {
+    expr = parse ":caption \"Hello, I am Katja\"";
+    expected = {
+      ":caption" = "Hello, I am Katja";
+    };
+  };
+
+}