Typst solution state

lib/typst/local/handout/0.1.0/solution.typ

@@ -1,34 +1,63 @@
 #import "misc.typ": ored, oblue
 
+
 /// If false, hide instructor info.
-///
-/// Compile with the following command to hide solutions:
-/// `typst compile main.typ --input show_solutions=false`
+/// If true, show it.
 ///
 /// Solutions are shown by default. This behavior
 /// is less surprising than hiding content by default.
-#let show_solutions = {
+#let solutions_state = state("solutions_state", true)
+
+/// Force solutions to be hidden after this point.
+///
+/// This function produces content that must be
+/// included in the document. If it is not included,
+/// this function will have no effect.
+#let hide_solutions() = {
+  return solutions_state.update(x => false)
+}
+
+/// Force solutions to be shown after this point.
+///
+/// This function produces content that must be
+/// included in the document. If it is not included,
+/// this function will have no effect.
+#let show_solutions() = {
+  return solutions_state.update(x => true)
+}
+
+
+
+/// Reset the solution flag to its default value.
+/// This value is determined by compile flags:
+/// Compile with the following command to hide solutions:
+/// `typst compile main.typ --input show_solutions=false`
+///
+/// Solutions are shown by default.
+///
+/// This function produces content that must be
+/// included in the document. If it is not included,
+/// this function will have no effect.
+#let reset_solutions() = {
   if "show_solutions" in sys.inputs {
-    // Show solutions unless they're explicitly disabled
-    not (
+    if (
       sys.inputs.show_solutions == "false" or sys.inputs.show_solutions == "no"
-    )
-  } else {
-    // Show solutions by default
-    true
+    ) {
+      return solutions_state.update(x => false)
+    }
   }
 }
 
-#let if_solutions(content) = {
-  if show_solutions { content }
+#let if_solutions(content) = context {
+  if solutions_state.get() { content }
 }
 
-#let if_no_solutions(content) = {
-  if not show_solutions { content }
+#let if_no_solutions(content) = context {
+  if not solutions_state.get() { content }
 }
 
-#let if_solutions_else(if_yes, if_no) = {
-  if show_solutions { if_yes } else { if_no }
+#let if_solutions_else(if_yes, if_no) = context {
+  if solutions_state.get() { if_yes } else { if_no }
 }
 
 #let solution(content) = {