Add support for different encodings (#210)

* Add support for different encodings

Add an '--encoding' flag to the CLI options to allow setting a custom
encoding.

When no encoding is passed, attempt to read the encoding from BOM
Tread as UTF-8 if all else fails.
This uses the encoding_rs_io crate to do this

Remove the dyn trait forSourceContainer as it's not required in this case

Add integration tests for lib methods

Author: ghaith

.vscode/launch.json

@@ -4,6 +4,7 @@
     // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
     "version": "0.2.0",
     "configurations": [
+
         {
             "type": "lldb",
             "request": "launch",
@@ -38,7 +39,7 @@
                     "kind": "bin"
                 }
             },
-            "args": ["examples/MainProg.st"],
+            "args": ["--ir", "examples/encoding.st"],
             "cwd": "${workspaceFolder}"
         },
         {

Cargo.lock

@@ -18,6 +18,8 @@ structopt = "0.3"
 indexmap = "1.6"
 chrono = "0.4"
 glob = "0.3.0"
+encoding_rs = "0.8"
+encoding_rs_io = "0.1"
 codespan-reporting = "0.11.1"
 
 

Cargo.toml

@@ -1,6 +1,8 @@
 PROGRAM hello
 VAR
-   x : INT;
+   x : INT
    y : BOOL;
 END_VAR
+   IF x = 2 THEN
+      x := 3
 END_PROGRAM