Command invocation

A global command may be invoked with a syntax that is similar to how it is declared. Thus the following forms exist:

Postfix invocation

A postfix _ some-command-name command is invoked with:

Some-expression some-command-name

Prefix invocation

A prefix not _ command is invoked with:

not Some-expression

Binary invocation

A binary _ + _ command is invoked with:

Some-expression + Other-expression

Keyword invocation

A keyword _ and: _ then: _ command is invoked with:

Some-expression
  and: Other-expression
  then: Another-expression

Self-less keyword invocation

A self-less keyword and: _ then: _ command is invoked with:

and: Some-expression then: Other-expression

Precedence rules

Crochet’s precedence rules are based more on the syntax of the command than on specific names. However, a few binary names are special. In the following list, expressions further down in the list can be included in the holes of expressions above it without parenthesis:

• Postfix <- Pipe (binary, store)

• Binary and: Binary then: Binary (keyword)

• Prefix === Prefix, Prefix as Type (binary, others)

• not Postfix (prefix)

• Simpler-expression some-name (postfix)

Associativity rules

Crochet requires explicit parenthesis for binary invocations by default. A convenience exception is made for binary commands that are associative as long as the sequence only includes that command. E.g. the following does not require parenthesis:

1 + 2 + 3 + 4

But the following does:

1 + 2 + (3 - 4)

Partial invocation

Any argument to a command can be the special hole (_) syntax, in which case the command is only partially applied, resulting in a partial program that can be, later on, further applied to other arguments.

It has the following syntax:

_ between: 1 and: 5