Add Dot-Dsl solution

Author: blogscot

dot-dsl/Cargo.toml

@@ -0,0 +1,6 @@
+[package]
+name = "dot-dsl"
+version = "0.1.0"
+
+[dependencies]
+maplit = "1.0.1"

dot-dsl/README.md

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+# DOT DSL
+
+Write a Domain Specific Language similar to the Graphviz dot language.
+
+A [Domain Specific Language
+(DSL)](https://en.wikipedia.org/wiki/Domain-specific_language) is a
+small language optimized for a specific domain.
+
+For example the [DOT language](https://en.wikipedia.org/wiki/DOT_(graph_description_language)) allows
+you to write a textual description of a graph which is then transformed into a picture by one of
+the [Graphviz](http://graphviz.org/) tools (such as `dot`). A simple graph looks like this:
+
+    graph {
+        graph [bgcolor="yellow"]
+        a [color="red"]
+        b [color="blue"]
+        a -- b [color="green"]
+    }
+
+Putting this in a file `example.dot` and running `dot example.dot -T png
+-o example.png` creates an image `example.png` with red and blue circle
+connected by a green line on a yellow background.
+
+Create a DSL similar to the dot language.
+
+## Builder pattern
+
+This exercise expects you to build several structs using `builder pattern`.
+In short, this pattern allows you to split the construction function of your struct, that contains a lot of arguments, into 
+several separate functions. This approuch gives you the means to make compact but highly-flexible struct construction and
+configuration.
+You can read more about it on the [following page](https://doc.rust-lang.org/1.0.0/style/ownership/builders.html).
+
+
+## Rust Installation
+
+Refer to the [exercism help page][help-page] for Rust installation and learning
+resources.
+
+## Writing the Code
+
+Execute the tests with:
+
+```bash
+$ cargo test
+```
+
+All but the first test have been ignored. After you get the first test to
+pass, open the tests source file which is located in the `tests` directory
+and remove the `#[ignore]` flag from the next test and get the tests to pass
+again. Each separate test is a function with `#[test]` flag above it.
+Continue, until you pass every test. 
+
+If you wish to run all tests without editing the tests source file, use:
+
+```bash
+$ cargo test -- --ignored
+```
+
+To run a specific test, for example `some_test`, you can use:
+
+```bash
+$ cargo test some_test
+```
+
+If the specific test is ignored use:
+
+```bash
+$ cargo test some_test -- --ignored
+```
+
+To learn more about Rust tests refer to the [online test documentation][rust-tests]
+
+Make sure to read the [Modules](https://doc.rust-lang.org/book/second-edition/ch07-00-modules.html) chapter if you
+haven't already, it will help you with organizing your files.
+
+## Feedback, Issues, Pull Requests
+
+The [exercism/rust](https://github.com/exercism/rust) repository on GitHub is the home for all of the Rust exercises. If you have feedback about an exercise, or want to help implement new exercises, head over there and create an issue. Members of the rust track team are happy to help!
+
+If you want to know more about Exercism, take a look at the [contribution guide](https://github.com/exercism/docs/blob/master/contributing-to-language-tracks/README.md).
+
+[help-page]: http://exercism.io/languages/rust
+[modules]: https://doc.rust-lang.org/book/second-edition/ch07-00-modules.html
+[cargo]: https://doc.rust-lang.org/book/second-edition/ch14-00-more-about-cargo.html
+[rust-tests]: https://doc.rust-lang.org/book/second-edition/ch11-02-running-tests.html
+
+## Submitting Incomplete Solutions
+It's possible to submit an incomplete solution so you can see how others have completed the exercise.

dot-dsl/src/lib.rs

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+pub mod graph {
+
+  use self::graph_items::edge::Edge;
+  use self::graph_items::node::Node;
+  use std::collections::HashMap;
+
+  pub mod graph_items {
+
+    pub mod edge {
+
+      #[derive(Clone, Debug, PartialEq)]
+      pub struct Edge {
+        start: String,
+        end: String,
+        attrs: Vec<(String, String)>,
+      }
+
+      impl Edge {
+        pub fn new(start: &str, end: &str) -> Self {
+          let start = start.to_string();
+          let end = end.to_string();
+          let attrs = Vec::new();
+          Edge { start, end, attrs }
+        }
+        pub fn with_attrs(mut self, attrs: &[(&str, &str)]) -> Self {
+          self.attrs = attrs
+            .iter()
+            .map(|attr| (attr.0.to_string(), attr.1.to_string()))
+            .collect();
+          self
+        }
+      }
+    }
+
+    pub mod node {
+
+      #[derive(Clone, Debug, PartialEq)]
+      pub struct Node {
+        label: String,
+        attrs: Vec<(String, String)>,
+      }
+
+      impl Node {
+        pub fn new(label: &str) -> Self {
+          let label = label.to_string();
+          let attrs = Vec::new();
+          Node { label, attrs }
+        }
+        pub fn with_attrs(mut self, attrs: &[(&str, &str)]) -> Self {
+          self.attrs = attrs
+            .iter()
+            .map(|attr| (attr.0.to_string(), attr.1.to_string()))
+            .collect();
+          self
+        }
+      }
+    }
+  }
+
+  #[derive(Default)]
+  pub struct Graph {
+    pub nodes: Vec<Node>,
+    pub edges: Vec<Edge>,
+    pub attrs: HashMap<String, String>,
+  }
+
+  impl Graph {
+    pub fn new() -> Self {
+      Graph::default()
+    }
+    pub fn with_nodes(mut self, nodes: &[Node]) -> Self {
+      self.nodes = nodes.to_vec();
+      self
+    }
+    pub fn with_edges(mut self, edges: &[Edge]) -> Self {
+      self.edges = edges.to_vec();
+      self
+    }
+    pub fn with_attrs(mut self, attrs: &[(&str, &str)]) -> Self {
+      self.attrs = attrs.iter().fold(HashMap::new(), |mut acc, attr| {
+        acc.insert((attr.0).to_string(), (attr.1).to_string());
+        acc
+      });
+      self
+    }
+  }
+}

dot-dsl/tests/dot-dsl.rs

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+#[macro_use]
+extern crate maplit;
+extern crate dot_dsl;
+
+use dot_dsl::graph::graph_items::edge::Edge;
+use dot_dsl::graph::graph_items::node::Node;
+use dot_dsl::graph::Graph;
+
+#[test]
+fn test_empty_graph() {
+  let graph = Graph::new();
+
+  assert!(graph.nodes.is_empty());
+
+  assert!(graph.edges.is_empty());
+
+  assert!(graph.attrs.is_empty());
+}
+
+#[test]
+fn test_graph_with_one_node() {
+  let nodes = vec![Node::new("a")];
+
+  let graph = Graph::new().with_nodes(&nodes);
+
+  assert!(graph.edges.is_empty());
+
+  assert!(graph.attrs.is_empty());
+
+  assert_eq!(graph.nodes, vec![Node::new("a")]);
+}
+
+#[test]
+fn test_graph_with_one_node_with_keywords() {
+  let nodes = vec![Node::new("a").with_attrs(&[("color", "green")])];
+
+  let graph = Graph::new().with_nodes(&nodes);
+
+  assert!(graph.edges.is_empty());
+
+  assert!(graph.attrs.is_empty());
+
+  assert_eq!(
+    graph.nodes,
+    vec![Node::new("a").with_attrs(&[("color", "green")])]
+  );
+}
+
+#[test]
+fn test_graph_with_one_edge() {
+  let edges = vec![Edge::new("a", "b")];
+
+  let graph = Graph::new().with_edges(&edges);
+
+  assert!(graph.nodes.is_empty());
+
+  assert!(graph.attrs.is_empty());
+
+  assert_eq!(graph.edges, vec![Edge::new("a", "b")]);
+}
+
+#[test]
+fn test_graph_with_one_attribute() {
+  let graph = Graph::new().with_attrs(&[("foo", "1")]);
+
+  let expected_attrs = hashmap!{
+      "foo".to_string() => "1".to_string(),
+  };
+
+  assert!(graph.nodes.is_empty());
+
+  assert!(graph.edges.is_empty());
+
+  assert_eq!(graph.attrs, expected_attrs);
+}
+
+#[test]
+fn test_graph_with_attributes() {
+  let nodes = vec![
+    Node::new("a").with_attrs(&[("color", "green")]),
+    Node::new("c"),
+    Node::new("b").with_attrs(&[("label", "Beta!")]),
+  ];
+
+  let edges = vec![
+    Edge::new("b", "c"),
+    Edge::new("a", "b").with_attrs(&[("color", "blue")]),
+  ];
+
+  let attrs = vec![("foo", "1"), ("title", "Testing Attrs"), ("bar", "true")];
+
+  let expected_attrs = hashmap! {
+      "foo".to_string() => "1".to_string(),
+      "title".to_string() => "Testing Attrs".to_string(),
+      "bar".to_string() => "true".to_string(),
+  };
+
+  let graph = Graph::new()
+    .with_nodes(&nodes)
+    .with_edges(&edges)
+    .with_attrs(&attrs);
+
+  assert_eq!(
+    graph.nodes,
+    vec![
+      Node::new("a").with_attrs(&[("color", "green")]),
+      Node::new("c"),
+      Node::new("b").with_attrs(&[("label", "Beta!")]),
+    ]
+  );
+
+  assert_eq!(
+    graph.edges,
+    vec![
+      Edge::new("b", "c"),
+      Edge::new("a", "b").with_attrs(&[("color", "blue")]),
+    ]
+  );
+
+  assert_eq!(graph.attrs, expected_attrs);
+}