Dynamic tree example

examples/dynamic-tree.rs

@@ -0,0 +1,80 @@
+//! This example constructs dynamic command tree from a structure
+
+use bpaf::*;
+
+#[derive(Debug, Clone)]
+enum Cog {
+    Command {
+        help: &'static str,
+        name: &'static str,
+        operation: &'static str,
+    },
+    Group {
+        name: &'static str,
+        help: &'static str,
+        nested: Vec<Cog>,
+    },
+}
+
+fn config() -> Cog {
+    let echo1 = Cog::Command {
+        help: "First echo command",
+        name: "echoCommand",
+        operation: "echo 'some text'",
+    };
+
+    let echo2 = Cog::Command {
+        help: "Second echo command",
+        name: "anotherEchoCmd",
+        operation: "echo 'another text'",
+    };
+    let sleep = Cog::Command {
+        name: "sleepCommand",
+        help: "sleep for a bit",
+        operation: "sleep 5",
+    };
+    let group1 = Cog::Group {
+        name: "commandGroup",
+        help: "contains a single sleep",
+        nested: vec![sleep],
+    };
+    Cog::Group {
+        name: "commands",
+        help: "contains all the commands, can be flattened with choose but effort :)",
+        nested: vec![echo1, echo2, group1],
+    }
+}
+
+fn choose<T>(xs: Vec<Box<dyn Parser<T> + 'static>>) -> Box<dyn Parser<T>>
+where
+    T: 'static,
+{
+    let mut items = xs.into_iter();
+
+    let mut res = items.next().unwrap();
+    for next in items {
+        res = construct!([res, next]).boxed()
+    }
+    res
+}
+
+fn make_parser(item: &Cog) -> Box<dyn Parser<&'static str>> {
+    match item {
+        Cog::Command {
+            help,
+            name,
+            operation,
+        } => Box::new(pure(*operation).to_options().descr(*help).command(name)),
+        Cog::Group { name, help, nested } => {
+            let nested = nested.iter().map(make_parser).collect::<Vec<_>>();
+            let inner = choose(nested);
+            inner.to_options().descr(*help).command(name).boxed()
+        }
+    }
+}
+
+fn main() {
+    let cfg = config();
+    let command = make_parser(&cfg).to_options().run();
+    println!("{:?}", command);
+}