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-rw-r--r--lib/default.nix1
-rw-r--r--lib/xml.nix84
2 files changed, 85 insertions, 0 deletions
diff --git a/lib/default.nix b/lib/default.nix
index 75086f864..8ba55b571 100644
--- a/lib/default.nix
+++ b/lib/default.nix
@@ -9,6 +9,7 @@ let
krops = import ../submodules/krops/lib;
shell = import ./shell.nix { inherit lib; };
types = nixpkgs-lib.types // import ./types.nix { inherit lib; };
+ xml = import ./xml.nix { inherit lib; };
eq = x: y: x == y;
ne = x: y: x != y;
diff --git a/lib/xml.nix b/lib/xml.nix
new file mode 100644
index 000000000..92f552154
--- /dev/null
+++ b/lib/xml.nix
@@ -0,0 +1,84 @@
+{ lib }:
+with lib;
+with builtins;
+rec {
+
+ # Use `term` to construct XML.
+ #
+ # Examples:
+ #
+ # (term "bool" null null)
+ # (term "cool" null [])
+ # (term "fool" { hurr = "durr"; } null)
+ # (term "hool" null [
+ # (term "tool" null null)
+ # ])
+ #
+ # See `render` for how these get transformed into actuall XML documents.
+ #
+ term = name: attrs: content: {
+ inherit name attrs content;
+ };
+
+ empty = term null null null;
+
+ # Ref http://www.w3.org/TR/xml/#syntax
+ #
+ # Example:
+ #
+ # (quote "<cheez!>") #===> &lt;cheez!&gt;
+ #
+ quote = let
+ sub = {
+ "&" = "&amp;";
+ "<" = "&lt;";
+ ">" = "&gt;";
+ "'" = "&apos;";
+ "\"" = "&quot;";
+ };
+ in
+ stringAsChars (c: sub.${c} or c);
+
+ # Turn an XML element to an XML document string.
+ doc = t:
+ "<?xml version='1.0' encoding='UTF-8'?>${render t}";
+
+ # Render an XML element to a string.
+ #
+ # Rendering `empty` yields the empty string.
+ #
+ # Examples:
+ #
+ # (term "bool" null null) #===> <bool/>
+ # (term "cool" null []) #===> <cool></cool>
+ # (term "fool" { hurr = "durr"; } null) #===> <fool hurr="durr"/>
+ # (term "hool" null [
+ # (term "tool" null null)
+ # ]) #===> <hool><tool/></hool>
+ #
+ render = let
+ render-attrs = attrs:
+ getAttr (typeOf attrs) {
+ null = "";
+ set = concatStrings (mapAttrsToList (n: v: " ${n}=\"${v}\"") attrs);
+ };
+
+ render-content = content:
+ getAttr (typeOf content) {
+ bool = toJSON content;
+ int = toJSON content;
+ list = concatMapStrings render content;
+ string = content;
+ };
+ in
+ { name, attrs, content }:
+ if name == null
+ then ""
+ else let
+ attrs' = render-attrs attrs;
+ content' = render-content content;
+ in
+ if content == null
+ then "<${name}${attrs'}/>"
+ else "<${name}${attrs'}>${content'}</${name}>";
+}