Changelog

Latest

4.1.0

New Features

• Enabled user-defined infixes for expressions and patterns: https://egison.readthedocs.io/en/latest/reference/basic-syntax.html#infix-declaration
• Allowed let expression to decompose data. Unlike match expressions (of Egison), this does not require matchers and the decomposition pattern is limited.

> let (x :: _) := [1, 2, 3] in x
1
> let (x :: _) := [] in x
Primitive data pattern match failed
  stack trace: <stdin>

• Enabled data decomposition at lambda arguments.

> (\(x, _) -> x) (1, 2)
1

• Implemented partial application.

> let add x y := x + y in map (add 1) [1, 2, 3]
[2, 3, 4]

• Huge speedup in mathematical programs:
  • Reimplemented math normalization, which was originally implemented in Egison, to the interpreter in Haskell.
  • Implemented lazy evaluation on tensor elements.
• Added new syntax for symmetric / anti-symmetric tensors.

Backward-incompatible Changes

• Changed the syntax to start definitions with def keyword.

def x := 1

• io was previously defined as a syntastic constructs, but it is changed into a primitive function. Namely, users will need to wrap the arguments to io in a parenthesis, or insert $ after io.

-- Invalid
io isEof ()

-- OK
io (isEOF ())
io $ isEOF ()

Miscellaneous

• Added a command line option --no-normalize to turn off math normalization implemented in the standard math library.
• Revived TSV input options: https://egison.readthedocs.io/en/latest/reference/command-line-options.html#reading-tsv-input
• Deprecated redefine.

4.0.3

• Renamed f.pi into pi.

4.0.1

• Fixed a bug of not-patterns inside sequential patterns.
• Deprecated procedure (replace them with anonymous function)

4.0.0

• Enabled the Haskell-like new syntax by default.