Merge pull request rust-lang#19 from 6A/kaleidoscope

Added Kaleidoscope example

Author: TheDan64

Cargo.toml

@@ -16,6 +16,10 @@ enum-methods = "0.0.7"
 libc = "*"
 llvm-sys = "37.0.5" # TODO: Configure based on feature toggle. GH#1
 
+[[example]]
+name = "kaleidoscope"
+path = "examples/kaleidoscope/main.rs"
+
 [badges]
 travis-ci = { repository = "TheDan64/inkwell" }
 codecov = { repository = "TheDan64/inkwell" }

examples/kaleidoscope/README.md

@@ -0,0 +1,46 @@
+# Kaleidoscope
+
+This example shows how one can implement the [Kaleidoscope programming language](https://llvm.org/docs/tutorial/index.html) using Inkwell.  
+It implements every feature up to the [7th chapter](https://llvm.org/docs/tutorial/LangImpl07.html).
+
+When running this example (using the `cargo run --example kaleidoscope` command), a prompt will be displayed; for example:
+
+```
+?> 1 + 1
+=> 2
+
+?> var a = 5, b = 10 in a * b
+=> 50
+
+?> def fib(n) if n < 2 then n else fib(n - 1) + fib(n - 2)
+
+?> fib(40)
+=> 102334155
+
+?>
+```
+
+Additional arguments can be passed to the produced executable:
+- `--dc`: **D**isplay **C**ompiler output
+- `--dp`: **D**isplay **P**arser output
+- `--dl`: **D**isplay **L**exer output
+
+For example, running with all three switches may lead to the following output:
+```
+?> 1 + 2 * 2
+-> Attempting to parse lexed input:
+[Number(1), Op('+'), Number(2), Op('*'), Number(2)]
+
+-> Expression parsed:
+Binary { op: '+', left: Number(1), right: Binary { op: '*', left: Number(2), right: Number(2) } }
+
+-> Expression compiled to IR:
+define double @anonymous() {
+entry:
+  ret double 5.000000e+00
+}
+
+=> 5
+```
+
+Finally, the prompt can be exited by entering "exit" or "quit".