1erl_recomment(3) Erlang Module Definition erl_recomment(3)
2
6 erl_recomment - Inserting comments into abstract Erlang syntax trees.
7
9 Inserting comments into abstract Erlang syntax trees
10 This module contains functions for inserting comments, described by po‐
12 sition, indentation and text, as attachments on an abstract syntax
13 tree, at the correct places.
14
16 syntaxTree() = erl_syntax:syntaxTree():
17 An abstract syntax tree. See the erl_syntax module for details.
20
22 quick_recomment_forms(Tree::erl_syntax:forms(), Cs::[erl_com‐
23 ment_scan:comment()]) -> erl_syntax:syntaxTree()
24 Like recomment_forms/2, but only inserts top-level comments.
26 Comments within function definitions or declarations ("forms")
27 are simply ignored.
28 recomment_forms(Tree::erl_syntax:forms(), Cs::[erl_comment_scan:com‐
30 ment()]) -> erl_syntax:syntaxTree()
31 Attaches comments to the syntax tree/trees representing a pro‐
33 gram. The given Forms should be a single syntax tree of type
34 form_list, or a list of syntax trees representing "program
35 forms". The syntax trees must contain valid position information
36 (for details, see recomment_tree/2). The result is a correspond‐
37 ing syntax tree of type form_list in which all comments in the
38 list Comments have been attached at the proper places.
39 Assuming Forms represents a program (or any sequence of "program
41 forms"), any comments whose first lines are not directly associ‐
42 ated with a specific program form will become standalone com‐
43 ments inserted between the neighbouring program forms. Further‐
44 more, comments whose column position is less than or equal to
45 one will not be attached to a program form that begins at a con‐
46 flicting line number (this can happen with preprocessor-gener‐
47 ated line-attributes).
48 If Forms is a syntax tree of some other type than form_list, the
50 comments will be inserted directly using recomment_tree/2, and
51 any comments left over from that process are added as postcom‐
52 ments on the result.
53 Entries in Comments represent multi-line comments. For each en‐
55 try, Line is the line number and Column the left column of the
56 comment (the column of the first comment-introducing "%" charac‐
57 ter). Indentation is the number of character positions between
58 the last non-whitespace character before the comment (or the
59 left margin) and the left column of the comment. Text is a list
60 of strings representing the consecutive comment lines in top-
61 down order, where each string contains all characters following
62 (but not including) the comment-introducing "%" and up to (but
63 not including) the terminating newline. (Cf. module erl_com‐
64 ment_scan.)
65 Evaluation exits with reason {bad_position, Pos} if the associ‐
67 ated position information Pos of some subtree in the input does
68 not have a recognizable format, or with reason {bad_tree, L, C}
69 if insertion of a comment at line L, column C, fails because the
70 tree structure is ill-formed.
71 See also: erl_comment_scan, quick_recomment_forms/2, recom‐
73 ment_tree/2.
74 recomment_tree(Tree::erl_syntax:syntaxTree(), Cs::[erl_com‐
76 ment_scan:comment()]) -> {erl_syntax:syntaxTree(), [erl_com‐
77 ment_scan:comment()]}
78 Attaches comments to a syntax tree. The result is a pair
80 {NewTree, Remainder} where NewTree is the given Tree where com‐
81 ments from the list Comments have been attached at the proper
82 places. Remainder is the list of entries in Comments which have
83 not been inserted, because their line numbers are greater than
84 those of any node in the tree. The entries in Comments are in‐
85 serted in order; if two comments become attached to the same
86 node, they will appear in the same order in the program text.
87 The nodes of the syntax tree must contain valid position infor‐
89 mation. This can be single integers, assumed to represent a line
90 number, or 2- or 3-tuples where the first or second element is
91 an integer, in which case the leftmost integer element is as‐
92 sumed to represent the line number. Line numbers less than one
93 are ignored (usually, the default line number for newly created
94 nodes is zero).
95 For details on the Line, Column and Indentation fields, and the
97 behaviour in case of errors, see recomment_forms/2.
98 See also: recomment_forms/2.
100
102 Richard Carlsson <carlsson.richard@gmail.com>
103 syntax_tools 2.6 erl_recomment(3)