langur

Langur is an open-source imperative/functional language written by Anthony Davis. Its principles of design are sensibility to humans, accuracy in calculation, and a clean, expressive syntax.

Influences include the following languages, and likely many others.

Perl, Go, Python, C#, C, SQL ... and Thorsten Ball's Monkey language, which was the starting point

The following is only a partial list of langur's features.

highly expressive given expressions (langur's “switch”)
semi-integrated regex
decimal floating point for numbers
number constants pi, phi, e, n2, n10
optional integer basex notation for any base from 2 to 36, such as -16xFF or 2x1010_0010
automated for loop over an array, hash, or string, or over a range
set a for loop value as it executes
useful built-in functions such as map(), fold(), where(), X(), mapX()
first-order functions, including closures
immutable or mutable declarations
decoupling assignments
block quote (similar to a "HEREDOC")
indexing strings by code point
indexing by arrays
chained string interpolation modifiers
truncating and floor division operators; also remainder and modulus, exponent and root
optional database operators (null propagating)
catching exceptions without explicit try blocks
a read() function that validates input

books

I initially developed langur following very useful books by Thorsten Ball (1, 2), but I've made many changes and additions.

I wrote langur to develop skills for another programming project. In the meantime, I wrote a book, explaining how some of langur's advanced features are designed to work in the stack-based virtual machine. See a free preview chapter at opcodebook.com.