Empty array vs. Empty list

An empty list is

[]

and an empty map is

{}

And empty array is

(,)

as it would cause ambiguity with a function / closure.

Type declaration vs. Initialisation

Declaration:

_myDict as Dictionary[of string, object]

Initialisation:

_myDict = Dictionary[of string, object]()

Assigning a Type vs. invoking a function

When you are calling a function don’t forget the brackets at the end.

Wrong:

fs = file.OpenRead

Correct:

fs = file.OpenRead()

If you make this mistake you will get errors like:

‘<method/property>’ is not a member of ‘<some type>’. (BCE0019)

Colon is the new semicolon

Remember the times when a missing semicolon used to be causing most compile errors, well, in boo it will be the missing colon which signifies a beginning of a block.

Wrong:

while ((line = filestream.ReadLine()) != null)

m.parse(line)

Correct:

while ((line = filestream.ReadLine()) != null):

m.parse(line)

If you forget the colon, you will get an error like:


Unexpected token: m. (BCE0043)
Unexpected token: <INDENT>. (BCE0043)
expecting "EOF", found '<DEDENT>'. (BCE0044)


Function definition in a script file

Maybe a no-brainer for python gurus, but if you have a script file, i.e. a file with no class, just instructions; functions are to be defined near the top of the script and called after it is def‘ed.

You can’t mix Boo with C# in same project

This is my mistake, but looking at samples having groovy and java files in same project; I blindly assumed that the same applies to Boo as well.

Intellisense / auto-complete does not work well.

Given the dynamic nature of Boo and maybe some bugs in SharpDevelop, it is not a great experience if you rely heavily on intellisense.

Embedding special characters in a string

Boo follows the python way of embedding special characters in string and not c#.

Wrong:

s = @“C:\path\to\dir\”

Correct:

s = “”"C:\path\to\dir\”"”

Embedding values in strings

The syntax is slightly weird, but useful nonetheless. You need to use both $ and enclose the variable in curly braces.

print “processing ${dir.Name}“

Still can’t find a way to pattern match and assign in the same line

I think this is possible, but I can’t figure a way to match a strung and assign the values to 2 variables.

I am trying to do something like, below and a few variations without luck:

key, val = /(?<key>[^=\s]+)\s*=\s*”(?<value>.+)”\s*$/.Match(line)

If the regex would have been simpler I could have used the Split instead of Match and things would have worked.

I ended up with something like:

data = /(?<key>[^=\s]+)\s*=\s*”(?<value>.+)”\s*$/.Match(line)

key, val = data.Groups["key"].Value, data.Groups["value"].Value

Embedding spaces in a regular expression patterns

As seen in the regex sample above, take extra care when you want to match a space. Use \s instead of a literal space.

Here is a list of programming languages available on these runtimes.

1. Can run on CLI using IKVM.NET
2. Can run on JVM using Mainsoft solution
3. Not yet usable
4. Can run on CLR, but is behind the JVM implementation

The main reason for the research was to identify a new language I should pick-up. I looked at Python and Ruby, but both have some sore thumbs that I just can’t stand. I really liked Boo and Groovy; they are similar to C#/Java in syntax and incorporate the good things from Python. Although I like Boo’s syntax and approach more than Groovy, Groovy has a more mature implementation and ecosystem. I will try to use Groovy for some hobby project and get a feel to things.