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|
-- Copyright 1999 Daniel Elphick and others
-- Licensed under Eiffel Forum Freeware License, version 1;
-- (see forum.txt)
%{
indexing
description: "XML parsing class"
author: "Daniel Elphick <de397@ecs.soton.ac.uk>"
class XML_PARSER
inherit
YY_PARSER_SKELETON [ANY]
rename
make as make_skeleton
redefine
report_error
end
XML_TOKENS
creation
make
%}
%token <STRING> TEXTUAL
%token <STRING> WHITE_SPACE
%token PI_START
%token PI_END
%token END_TAG_START
%type <LINKED_LIST[ANY]> tags
%type <TAG_TREE> tag
%type <TAG_TREE> xml_file
%type <STRING> start_tag
%type <STRING> end_tag
%type <STRING> pi_tag
%% -- Grammar rules and actions follow.
xml_file : pi_tag tags
{
!!tree.make("ROOT")
tree.add_child($1)
tree.add_children($2)
$$ := tree
}
;
tag : start_tag tags end_tag
{
if $1.is_equal($3) then
!!$$.make($1)
$$.add_children($2)
else
std.error.put_string("Start tag '")
std.error.put_string($1)
std.error.put_string("' does not match end tag '")
std.error.put_string($3)
std.error.put_string("'%N")
raise_error
end
}
| start_tag TEXTUAL end_tag
{
if $1.is_equal($3) then
!!$$.make($1)
$$.add_child($2)
else
std.error.put_string("Start tag '")
std.error.put_string($1)
std.error.put_string("' does not match end tag '")
std.error.put_string($3)
std.error.put_string("'%N")
raise_error
end
}
;
tags : tags tag
{
$1.add_last($2)
$$ := $1
}
|
{
!!$$.make
}
;
start_tag : '<' TEXTUAL '>'
{
$$ := $2
}
;
end_tag : END_TAG_START TEXTUAL '>'
{
$$ := $2
}
;
pi_tag : PI_START TEXTUAL PI_END
{
$$ := $2
}
;
%%
feature
tree: TAG_TREE
input: INPUT_STREAM
line_number: INTEGER
make(stream: INPUT_STREAM) is
do
input := stream
line_number := 1
make_skeleton
state := initial
end
expand_last_value is
local
i: INTEGER
temp: STRING
do
temp := last_value
!!last_value.make(temp.count)
from
i := 1
until
i > temp.count
loop
inspect
temp @ i
when '%N' then
last_value.append("%%N")
when '%T' then
last_value.append("%%T")
when '%%' then
last_value.append("%%%%")
when '&' then
if (temp.count - i) >= 3 then
if (temp @ (i + 1)) = 'g' then
if (temp @ (i + 2)) = 't' and then
(temp @ (i + 3)) = ';' then
i := i + 3
last_value.append_character('>')
else
last_value.append_character('&')
end
elseif (temp @ (i + 1)) = 'l' then
if (temp @ (i + 2)) = 't' and then
(temp @ (i + 3)) = ';' then
i := i + 3
last_value.append_character('<')
else
last_value.append_character('&')
end
else
last_value.append_character('&')
end
else
last_value.append_character('&')
end
else
last_value.append_character(temp @ i)
end
i := i + 1
end
end
state: INTEGER
pending_character: CHARACTER
has_pending_character: BOOLEAN
last_character: CHARACTER
last_value: STRING
last_token: INTEGER
error: INTEGER is -1
yyEOF_token: INTEGER is 0
initial: INTEGER is 1
expect: INTEGER is 2
expect_pi_end: INTEGER is 3
expect_start_end: INTEGER is 4
expect_end_end: INTEGER is 5
in_pi: INTEGER is 6
in_start: INTEGER is 7
in_end: INTEGER is 8
weird: INTEGER is 9
report_error(a_message: STRING) is
do
std.error.put_string(a_message)
std.error.put_string(" at line ")
std.error.put_integer(line_number)
std.error.put_character('%N')
std.error.put_string("last_token = ")
std.error.put_integer(last_token)
std.error.put_character('%N')
std.error.put_string("last_character = '")
std.error.put_character(last_character)
std.error.put_string("'%N")
std.error.put_string("state = ")
std.error.put_integer(state)
std.error.put_string("%N")
end
read_token is
do
!!last_value.make(0)
if has_pending_character then
last_character := input.last_character
has_pending_character := False
else
input.read_character
if not input.end_of_input then
last_character := input.last_character
if last_character = '%N' then
line_number := line_number + 1
end
else
last_token := yyEOF_token
state := yyEOF_token
end
end
inspect
state
when initial then
last_token := 9999 -- not a token but > yyEOF_token
from
until
last_character = '<' or else last_token <= yyEOF_token
loop
if not ("%T%N <").has(last_character) then
std.error.put_string("Error in INITIAL state%N")
last_token := error
else
input.read_character
if not input.end_of_input then
last_character := input.last_character
if last_character = '%N' then
line_number := line_number + 1
end
else
last_token := yyEOF_token
end
end
end
if last_token /= error and last_token /= yyEOF_token then
state := expect
read_token
end
when weird then
from
last_token := 0
until
last_character = '<' or else last_token = error
loop
if last_character = '>' then
std.error.put_string("Error in WEIRD state%N")
last_token := error
else
if not (" %T%N").has(last_character) then
last_token := TEXTUAL
from
until
last_character = '<' or else last_token = error
loop
if last_character = '>' then
last_token := error
else
last_value.append_character(last_character)
input.read_character
if input.end_of_input then
std.error.put_string("Error in WEIRD state%N")
last_token := error
else
last_character := input.last_character
if last_character = '%N' then
line_number := line_number + 1
end
end
end
end
else
last_value.append_character(last_character)
input.read_character
if input.end_of_input then
std.error.put_string("Error in WEIRD state%N")
last_token := error
else
last_character := input.last_character
if last_character = '%N' then
line_number := line_number + 1
end
end
end
end
end
state := expect
if last_token = 0 then
input.read_character
if not input.end_of_input then
if input.last_character = '/' then
last_token := TEXTUAL
expand_last_value
input.unread_character
else
input.unread_character
read_token
end
end
elseif last_token = TEXTUAL then
expand_last_value
end
when expect then
inspect
last_character
when '?' then
last_token := PI_START
state := in_pi
when '/' then
last_token := END_TAG_START
state := in_end
else
last_token := ('<').code
state := in_start
pending_character := last_character
has_pending_character := True
end
when expect_pi_end then
if last_character = '>' then
last_token := PI_END
state := initial
else
std.error.put_string("Error in EXPECT_PI_END state%N")
last_token := error
end
when expect_start_end then
if last_character = '>' then
last_token := ('>').code
state := weird
else
std.error.put_string("Error in EXPECT_START_END state%N")
last_token := error
end
when expect_end_end then
if last_character = '>' then
last_token := ('>').code
state := initial
else
std.error.put_string("Error in EXPECT_END_END state%N")
last_token := error
end
when in_pi then
from
until
last_character = '>' or else last_token = error
loop
if last_character /= '<' then
last_value.append_character(last_character)
input.read_character
if not input.end_of_input then
last_character := input.last_character
if last_character = '%N' then
line_number := line_number + 1
end
else
std.error.put_string("Error in IN_PI state%N")
last_token := error
end
else
last_token := error
end
end
if last_token /= error and then last_value.item(last_value.count) = '?' then
last_value.remove_last(1) -- strip off '?'
pending_character := '>'
has_pending_character := True
last_token := TEXTUAL
state := expect_pi_end
else
std.error.put_string("Error in IN_PI state%N")
last_token := error
end
when in_start then
from
until
last_character = '>' or else last_token = error
loop
if last_character /= '<' then
last_value.append_character(last_character)
input.read_character
if not input.end_of_input then
last_character := input.last_character
if last_character = '%N' then
line_number := line_number + 1
end
else
std.error.put_string("Error in IN_START state%N")
last_token := error
end
else
std.error.put_string("Error in IN_START state%N")
last_token := error
end
end
if last_token /= error then
pending_character := '>'
has_pending_character := True
last_token := TEXTUAL
state := expect_start_end
end
when in_end then
from
until
last_character = '>' or else last_token = error
loop
if last_character /= '<' then
last_value.append_character(last_character)
input.read_character
if not input.end_of_input then
last_character := input.last_character
if last_character = '%N' then
line_number := line_number + 1
end
else
std.error.put_string("Error in IN_START state%N")
last_token := error
end
else
std.error.put_string("Error in IN_START state%N")
last_token := error
end
end
if last_token /= error then
pending_character := '>'
has_pending_character := True
last_token := TEXTUAL
state := expect_end_end
end
when 0 then
else
print("How did we get here?%N")
die_with_code(exit_failure_code)
end
end
end
|
