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Diffstat (limited to 'lib/docbuilder/src/docb_pretty_format.erl')
| -rw-r--r-- | lib/docbuilder/src/docb_pretty_format.erl | 177 |
1 files changed, 177 insertions, 0 deletions
diff --git a/lib/docbuilder/src/docb_pretty_format.erl b/lib/docbuilder/src/docb_pretty_format.erl new file mode 100644 index 0000000000..0c4fb0507b --- /dev/null +++ b/lib/docbuilder/src/docb_pretty_format.erl @@ -0,0 +1,177 @@ +%% ``The contents of this file are subject to the Erlang Public License, +%% Version 1.1, (the "License"); you may not use this file except in +%% compliance with the License. You should have received a copy of the +%% Erlang Public License along with this software. If not, it can be +%% retrieved via the world wide web at http://www.erlang.org/. +%% +%% Software distributed under the License is distributed on an "AS IS" +%% basis, WITHOUT WARRANTY OF ANY KIND, either expressed or implied. See +%% the License for the specific language governing rights and limitations +%% under the License. +%% +%% The Initial Developer of the Original Code is Ericsson Utvecklings AB. +%% Portions created by Ericsson are Copyright 1999-2000, Ericsson +%% Utvecklings AB. All Rights Reserved.'' +%% +%% $Id$ +%% +-module(docb_pretty_format). + +-export([term/1]). + +%% pretty_format:term(Term) -> PNF list of characters +%% +%% Note: this is usually used in expressions like: +%% io:format('~s\n', [pretty_format:term(Term)]). +%% +%% Uses the following simple heuristics: +%% +%% 1) Simple tuples are printed across the page. +%% (Simple means *all* the elements are "flat") +%% 2) The complex tuple {Arg1, Arg2, Arg3,....} is printed thus: +%% {Arg1, +%% Arg2, +%% Arg3, +%% ...} +%% 3) Lists are treated as for tuples. +%% 4) Lists of printable characters are treated as strings. +%% +%% This method seems to work reasonable well for {Tag, ...} type +%% data structures. +term(Term) -> + element(2, term(Term, 0)). + +%% pretty_format:term(Term, Indent} -> {Indent', Chars} +%% Format <Term> -- use <Indent> to indent the *next* line. +%% Note: Indent' is a new indentaion level (sometimes printing <Term> +%% the next line to need an "extra" indent!). +term([], Indent) -> + {Indent, [$[,$]]}; +term(L, Indent) when list(L) -> + case is_string(L) of + true -> + {Indent, io_lib:write_string(L)}; + false -> + case complex_list(L) of + true -> + write_complex_list(L, Indent); + false -> + write_simple_list(L, Indent) + end + end; +term(T, Indent) when tuple(T) -> + case complex_tuple(T) of + true -> + write_complex_tuple(T, Indent); + false -> + write_simple_tuple(T, Indent) + end; +term(A, Indent) -> + {Indent, io_lib:write(A)}. + +%% write_simple_list([H|T], Indent) -> {Indent', Chars} +write_simple_list([H|T], Indent) -> + {_, S1} = term(H, Indent), + {_, S2} = write_simple_list_tail(T, Indent), + {Indent, [$[,S1|S2]}. + +write_simple_list_tail([H|T], Indent) -> + {_, S1} = term(H, Indent), + {_, S2} = write_simple_list_tail(T, Indent), + {Indent, [$,,S1| S2]}; +write_simple_list_tail([], Indent) -> + {Indent, "]"}; +write_simple_list_tail(Other, Indent) -> + {_, S} = term(Other, Indent), + {Indent, [$|,S,$]]}. + +%% write_complex_list([H|T], Indent) -> {Indent', Chars} +write_complex_list([H|T], Indent) -> + {I1, S1} = term(H, Indent+1), + {_, S2} = write_complex_list_tail(T, I1), + {Indent, [$[,S1|S2]}. + +write_complex_list_tail([H|T], Indent) -> + {I1, S1} = term(H, Indent), + {_, S2} = write_complex_list_tail(T, I1), + {Indent, [$,,nl_indent(Indent),S1,S2]}; +write_complex_list_tail([], Indent) -> + {Indent, "]"}; +write_complex_list_tail(Other, Indent) -> + {_, S} = term(Other, Indent), + {Indent, [$|,S,$]]}. + +%% complex_list(List) -> true | false +%% Returns true if the list is complex otherwise false. +complex_list([]) -> + false; +complex_list([H|T]) when is_list(H) -> + case is_string(H) of + true -> + complex_list(T); + false -> + true + end; +complex_list([H|_]) when is_tuple(H) -> true; +complex_list(_) -> false. + +%% complex_tuple(Tuple) -> true | false +%% Returns true if the tuple is complex otherwise false. +complex_tuple(T) -> + complex_list(tuple_to_list(T)). + +%% write_simple_tuple(Tuple, Indent} -> {Indent', Chars} +write_simple_tuple({}, Indent) -> + {Indent, "{}"}; +write_simple_tuple(Tuple, Indent) -> + {_, S} = write_simple_tuple_args(tuple_to_list(Tuple), Indent), + {Indent, [${, S, $}]}. + +write_simple_tuple_args([X], Indent) -> + term(X, Indent); +write_simple_tuple_args([H|T], Indent) -> + {_, SH} = term(H, Indent), + {_, ST} = write_simple_tuple_args(T, Indent), + {Indent, [SH, $,, ST]}. + +%% write_complex_tuple(Tuple, Indent} -> {Indent', Chars} +write_complex_tuple(Tuple, Indent) -> + [H|T] = tuple_to_list(Tuple), + {I1, SH} = term(H, Indent+2), + {_, ST} = write_complex_tuple_args(T, I1), + {Indent, [${, SH, ST, $}]}. + +write_complex_tuple_args([X], Indent) -> + {_, S} = term(X, Indent), + {Indent, [$,, nl_indent(Indent), S]}; +write_complex_tuple_args([H|T], Indent) -> + {I1, SH} = term(H, Indent), + {_, ST} = write_complex_tuple_args(T, I1), + {Indent, [$,, nl_indent(Indent) , SH, ST]}; +write_complex_tuple_args([], Indent) -> + {Indent, []}. + +%% utilities + +nl_indent(I) when I >= 0 -> + ["\n"|indent(I)]; +nl_indent(_I) -> + [$ ]. + +indent(I) when I >= 8 -> + [$\t|indent(I-8)]; +indent(I) when I > 0 -> + [$ |indent(I-1)]; +indent(_) -> + []. + +is_string([9|T]) -> + is_string(T); +is_string([10|T]) -> + is_string(T); +is_string([H|T]) when H >31, H < 127 -> + is_string(T); +is_string([]) -> + true; +is_string(_) -> + false. |