erl_recomment(3erl) Erlang Module Definition erl_recomment(3erl)
NAME
erl_recomment - Inserting comments into abstract Erlang syntax trees.
DESCRIPTION
Inserting comments into abstract Erlang syntax trees
This module contains functions for inserting comments, described by po-
sition, 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:
Forms = syntaxTree() | [syntaxTree()]
Comment = {Line, Column, Indentation, Text}
Line = integer()
Column = integer()
Indentation = integer()
Text = [string()]
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:
Forms = syntaxTree() | [syntaxTree()]
Comment = {Line, Column, Indentation, Text}
Line = integer()
Column = integer()
Indentation = integer()
Text = [string()]
Attaches comments to the syntax tree/trees representing a pro-
gram. 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 correspond-
ing 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 associ-
ated with a specific program form will become standalone com-
ments inserted between the neighbouring program forms. Further-
more, comments whose column position is less than or equal to
one will not be attached to a program form that begins at a con-
flicting line number (this can happen with preprocessor-gener-
ated 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 postcom-
ments on the result.
Entries in Comments represent multi-line comments. For each en-
try, Line is the line number and Column the left column of the
comment (the column of the first comment-introducing "%" charac-
ter). 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_com-
ment_scan.)
Evaluation exits with reason {bad_position, Pos} if the associ-
ated 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, recom-
ment_tree/2.
recomment_tree(Tree::syntaxTree(), Comments::[Comment]) -> {syntax-
Tree(), [Comment]}
Types:
Comment = {Line, Column, Indentation, Text}
Line = integer()
Column = integer()
Indentation = integer()
Text = [string()]
Attaches comments to a syntax tree. The result is a pair
{NewTree, Remainder} where NewTree is the given Tree where com-
ments 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 in-
serted 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 infor-
mation. 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 as-
sumed 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.
AUTHORS
Richard Carlsson <carlsson.richard@gmail.com>
syntax_tools 2.3 erl_recomment(3erl)