erl_recomment
Module
erl_recomment
Module Summary
Inserting comments into abstract Erlang syntax trees.
Description
Inserting comments into abstract Erlang syntax trees
This module contains functions for inserting comments, described by position, indentation and text, as attachments on an abstract syntax tree, at the correct places.
Data types
- syntaxTree() =
erl_syntax:syntaxTree()
-
An abstract syntax tree. See the
erl_syntax
module for details.
Exports
quick_recomment_forms(Tree::Forms, Comments::[Comment]) -> syntaxTree() |
Types
Like recomment_forms/2
, but only inserts top-level comments. Comments within function definitions or declarations ("forms") are simply ignored.
recomment_forms(Tree::Forms, Comments::[Comment]) -> syntaxTree() |
Types
Attaches comments to the syntax tree/trees representing a program. The given Forms
should be a single syntax tree of type form_list
, or a list of syntax trees representing "program forms". The syntax trees must contain valid position information (for details, see recomment_tree/2
). The result is a corresponding syntax tree of type form_list
in which all comments in the list Comments
have been attached at the proper places.
Assuming Forms
represents a program (or any sequence of "program forms"), any comments whose first lines are not directly associated with a specific program form will become standalone comments inserted between the neighbouring program forms. Furthermore, comments whose column position is less than or equal to one will not be attached to a program form that begins at a conflicting line number (this can happen with preprocessor-generated line
-attributes).
If Forms
is a syntax tree of some other type than form_list
, the comments will be inserted directly using recomment_tree/2
, and any comments left over from that process are added as postcomments on the result.
Entries in Comments
represent multi-line comments. For each entry, Line
is the line number and Column
the left column of the comment (the column of the first comment-introducing "%
" character). Indentation
is the number of character positions between the last non-whitespace character before the comment (or the left margin) and the left column of the comment. Text
is a list of strings representing the consecutive comment lines in top-down order, where each string contains all characters following (but not including) the comment-introducing "%
" and up to (but not including) the terminating newline. (Cf. module erl_comment_scan
.)
Evaluation exits with reason {bad_position, Pos}
if the associated position information Pos
of some subtree in the input does not have a recognizable format, or with reason {bad_tree, L, C}
if insertion of a comment at line L
, column C
, fails because the tree structure is ill-formed.
See also: erl_comment_scan
, quick_recomment_forms/2
, recomment_tree/2
.
recomment_tree(Tree::syntaxTree(), Comments::[Comment]) -> {syntaxTree(), [Comment]} |
Types
Attaches comments to a syntax tree. The result is a pair {NewTree, Remainder}
where NewTree
is the given Tree
where comments from the list Comments
have been attached at the proper places. Remainder
is the list of entries in Comments
which have not been inserted, because their line numbers are greater than those of any node in the tree. The entries in Comments
are inserted in order; if two comments become attached to the same node, they will appear in the same order in the program text.
The nodes of the syntax tree must contain valid position information. This can be single integers, assumed to represent a line number, or 2- or 3-tuples where the first or second element is an integer, in which case the leftmost integer element is assumed to represent the line number. Line numbers less than one are ignored (usually, the default line number for newly created nodes is zero).
For details on the Line
, Column
and Indentation
fields, and the behaviour in case of errors, see recomment_forms/2
.
See also: recomment_forms/2
.
© 2010–2020 Ericsson AB
Licensed under the Apache License, Version 2.0.