guess-external-format

guess-external-format Function

Summary

Tries to work out the external format.

Package

system

Signature

guess-external-format pathname ef-spec buffer length => ef-spec

Arguments

`pathname`⇩	Pathname identifying location of `buffer`.
`ef-spec`⇩	An external format spec.
`buffer`⇩	A buffer whose contents are examined.
`length`⇩	Length (an integer) up to which `buffer` should be examined.

Values

ef-spec

An external format spec.

Description

The function guess-external-format tries to detect any unspecified components of ef-spec using pathname and buffer (bounded by length).

If ef-spec is complete, then it is returned. Otherwise guess-external-format calls, in turn, functions on the list *file-encoding-detection-algorithm*. If a complete external format spec is returned it is used, otherwise the return value is passed to the next function. If the name of the external format spec returned by the last function on this list is :default, an error of type file-encoding-resolution-error is signaled. Otherwise guess-external-format proceeds to guess the eol-style.

To guess the eol-style, functions on the list *file-eol-style-detection-algorithm* are called in turn. If a complete external format spec is returned it is used, otherwise the return value is passed to the next function. If the external format spec returned by the last function on this list does not contain :eol-style, an error of type file-encoding-resolution-error is signaled.