:examples: ../examples/

= Debug Tree

This library allows you to build a tree one element at a time and output it as a pretty string.

The tree can easily be output to a String, stdout or a file.

This is particularly convenient for generating clean output from nested and recursive functions.

:toc:

== Recursive Fibonacci Example

Using the add_branch!() macro at the start of the factors() function, you can generate an entire call tree, with minimal effort.

[source,rust]

use debug_tree::*;

fn factors(x: usize) { add_branch!("{}", x); // <~ THE MAGIC LINE for i in 1..x { if x % i == 0 { factors(i); } } }

fn main() { // output to file at the end of this block deferwrite!("examples/out/fibonacci.txt"); addbranch!("A Fibonacci Tree"); factors(6); add_leaf!("That's All Folks!");

}

A Fibonacci Tree ├╼ 6 │ ├╼ 1 │ ├╼ 2 │ │ └╼ 1 │ └╼ 3 │ └╼ 1

└╼ That's All Folks!

== Overview

• Add a branch
• add_branch!("Hello, {}", "World")

• The branch will exit at the end of the current block

• Add a leaf

• add_leaf!("I am a {}", "leaf")

• Added to the current scoped branch

• Print a tree, or write it to file at the end of a block

• defer_print!()
• defer_write!("filename.txt")
• The tree will be empty after these calls

• To prevent clearing, use defer_peek_print! and defer_peek_write!

• Get the trees pretty-string -

• Handle multiple trees using named trees

• add_branch_to!("A", "I'm a branch on tree 'A'")
• add_leaf_to!("A", "I'm a leaf on tree 'A'")
• defer_print!("A")

• defer_write!("A", "filename.txt")

• Get a named tree

• tree("TREE_NAME")

• Retrieve the pretty-string from a tree

• tree("TREE_NAME").string()

• Usage across threads

• default_tree() is local to each thread
• Named trees are shared between threads

== More Examples

=== Multiple Tagged Trees

If you need multiple, separated trees you can use a name tag.

[source,rust]

use debug_tree::*;

fn populate(treename: &str, nchildren: usize) { addbranchto!(treename, "{} TREE", treename); for _ in 0..nchildren { populate(treename, nchildren / 2); } } fn main() { // Override tree config (just for "B") let btree = tree("B"); btree.setconfigoverride( TreeConfig::new() .indent(4) .symbols(TreeSymbols::withrounded().leaf("> ")), ); deferwrite!(btree, "examples/out/multipletreesB.txt"); deferwrite!("A", "examples/out/multipletrees_A.txt");

populate("A", 2);
populate("B", 3);

}

A TREE ├╼ A TREE │ └╼ A TREE └╼ A TREE

└╼ A TREE

B TREE ├──> B TREE │ ╰──> B TREE ├──> B TREE │ ╰──> B TREE ╰──> B TREE

╰──> B TREE

=== Nested Functions

Branches also make nested function calls a lot easier to follow.

[source,rust]

use debugtree::*; fn a() { addbranch!("a"); b(); c(); } fn b() { addbranch!("b"); c(); } fn c() { addbranch!("c"); add_leaf!("Nothing to see here"); }

fn main() { defer_write!("examples/out/nested.txt"); a();

}

a ├╼ b │ └╼ c │ └╼ Nothing to see here └╼ c

└╼ Nothing to see here

=== Line Breaks

Newlines in multi-line strings are automatically indented.

[source,rust]

use debugtree::*; fn main() { // output to file at the end of this block deferwrite!("examples/out/multiline.txt"); addbranch!("1"); addleaf!("1.1\nAnother line...\n... and one more line"); addleaf!("1.2");

}

1 ├╼ 1.1 │ Another line... │ ... and one more line

└╼ 1.2

=== Panics Even if there is a panic, the tree is not lost! The defer_ functions were introduced to allow the tree to be printed our written to file in the case of a panic! or early return.

[source,rust]

use debug_tree::*;

fn iwillpanic() { addbranch!("Here are my last words"); addleaf!("Stay calm, and try not to panic"); panic!("I told you so...") }

fn main() { // output to file at the end of this block deferwrite!("examples/out/panic.txt"); // print at the end of this block { addbranch!("By using the 'defer' functions"); addbranch!("Output will still be generated"); addbranch!("Otherwise you might lose your valuable tree!"); } addbranch!("Now for something crazy..."); iwillpanic();

}

By using the 'defer_' functions └╼ Output will still be generated └╼ Otherwise you might lose your valuable tree! Now for something crazy... └╼ Here are my last words

└╼ Stay calm, and try not to panic

=== Without Macros

If you prefer not using macros, you can construct TreeBuilders manually.

[source,rust]

use debug_tree::TreeBuilder;

fn main() { // Make a new tree. let tree = TreeBuilder::new();

// Add a scoped branch. The next item added will belong to the branch.
let mut branch = tree.add_branch("1 Branch");

// Add a leaf to the current branch
tree.add_leaf("1.1 Child");

// Leave scope early
branch.release();
tree.add_leaf("2 Sibling");
// output to file
tree.write("examples/out/no_macros.txt").ok(); // Write and flush.

}

1 Branch └╼ 1.1 Child

2 Sibling