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Add FindLongestMatchResult

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This commit is contained in:
Josh Holtrop 2023-06-04 21:14:07 -04:00
parent 6b0fb4cb12
commit 11348ca351
1 changed files with 178 additions and 66 deletions
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244
assets/parser.d.erb
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@ -267,14 +267,6 @@ class <%= @classname %>
<% end %>
];
struct MatchInfo
{
size_t length;
size_t delta_row;
size_t delta_col;
const(State) * accepting_state;
}
struct Result
{
enum Type
@ -282,6 +274,7 @@ class <%= @classname %>
DECODE_ERROR,
DROP,
TOKEN,
UNEXPECTED_INPUT,
}
Type type;
@ -349,99 +342,218 @@ class <%= @classname %>
result.row = m_input_row;
result.col = m_input_col;
result.token = _TOKEN_COUNT;
MatchInfo match_info;
find_longest_match(&result, &match_info);
if (result.token != _TOKEN_COUNT)
auto match_result = find_longest_match();
if (match_result.is_eof())
{
result.type = Result.Type.TOKEN;
result.token = TOKEN___EOF;
return result;
}
if (match_info.accepting_state != null)
else if (match_result.is_decode_error())
{
uint token_to_accept = match_info.accepting_state.token;
if (match_info.accepting_state.code_id.is_valid())
result.type = Result.Type.DECODE_ERROR;
return result;
}
else if (match_result.is_unexpected_input())
{
result.type = Result.Type.UNEXPECTED_INPUT;
return result;
}
uint token_to_accept = match_result.accepting_state.token;
if (match_result.accepting_state.code_id.is_valid())
{
Token user_code_token = user_code(match_result.accepting_state.code_id, m_input[m_input_position..(m_input_position + match_result.length)], &result);
/* An invalid Token from user_code() means that the user
* code did not explicitly return a token. So only override
* the token to return if the user code does explicitly
* return a token. */
if (user_code_token.is_valid())
{
Token user_code_token = user_code(match_info.accepting_state.code_id, m_input[m_input_position..(m_input_position + match_info.length)], &result);
/* An invalid Token from user_code() means that the user
* code did not explicitly return a token. So only override
* the token to return if the user code does explicitly
* return a token. */
if (user_code_token.is_valid())
{
token_to_accept = user_code_token.token;
}
token_to_accept = user_code_token.token;
}
}
/* Update the input position tracking. */
m_input_position += match_info.length;
m_input_row += match_info.delta_row;
if (match_info.delta_row != 0u)
{
m_input_col = match_info.delta_col;
}
else
{
m_input_col += match_info.delta_col;
}
result.token = token_to_accept;
result.length = match_info.length;
if (match_info.accepting_state.drop)
{
result.type = Result.Type.DROP;
}
else
{
result.type = Result.Type.TOKEN;
}
/* Update the input position tracking. */
m_input_position += match_result.length;
m_input_row += match_result.delta_row;
if (match_result.delta_row != 0u)
{
m_input_col = match_result.delta_col;
}
else
{
m_input_col += match_result.delta_col;
}
result.token = token_to_accept;
result.length = match_result.length;
if (match_result.accepting_state.drop)
{
result.type = Result.Type.DROP;
}
else
{
result.type = Result.Type.TOKEN;
}
return result;
}
private void find_longest_match(Result * result, MatchInfo * match_info)
/**
* Result type for find_longest_match().
*
* Alternatives:
* - decode_error
* - eof
* - found_match(length, delta_row, delta_col, accepting_state)
* - unexpected_input(unexpected_input_length)
*/
struct FindLongestMatchResult
{
MatchInfo attempt_match_info;
enum : ubyte
{
FOUND_MATCH,
DECODE_ERROR,
EOF,
UNEXPECTED_INPUT,
}
ubyte type;
alias type this;
union
{
struct
{
size_t length;
size_t delta_row;
size_t delta_col;
const(State) * accepting_state;
}
size_t unexpected_input_length;
}
this(ubyte type)
{
this.type = type;
}
this(ubyte type, size_t unexpected_input_length)
{
this.type = type;
this.unexpected_input_length = unexpected_input_length;
}
this(ubyte type, size_t length, size_t delta_row, size_t delta_col, const(State) * accepting_state)
{
this.type = type;
this.length = length;
this.delta_row = delta_row;
this.delta_col = delta_col;
this.accepting_state = accepting_state;
}
static FindLongestMatchResult found_match(size_t length, size_t delta_row, size_t delta_col, const(State) * accepting_state)
{
return FindLongestMatchResult(FOUND_MATCH, length, delta_row, delta_col, accepting_state);
}
static FindLongestMatchResult decode_error()
{
return FindLongestMatchResult(DECODE_ERROR);
}
static FindLongestMatchResult eof()
{
return FindLongestMatchResult(EOF);
}
static FindLongestMatchResult unexpected_input(size_t unexpected_input_length)
{
return FindLongestMatchResult(UNEXPECTED_INPUT, unexpected_input_length);
}
bool is_found_match()
{
return type == FOUND_MATCH;
}
bool is_decode_error()
{
return type == DECODE_ERROR;
}
bool is_eof()
{
return type == EOF;
}
bool is_unexpected_input()
{
return type == UNEXPECTED_INPUT;
}
}
private FindLongestMatchResult find_longest_match()
{
FindLongestMatchResult longest_match = FindLongestMatchResult.found_match(0, 0, 0, null);
FindLongestMatchResult attempt_match = longest_match;
uint current_state = modes[m_mode].state_table_offset;
for (;;)
{
auto decoded = Decoder.decode_code_point(m_input[(m_input_position + attempt_match_info.length)..(m_input.length)]);
auto decoded = Decoder.decode_code_point(m_input[(m_input_position + attempt_match.length)..(m_input.length)]);
if (decoded.is_decode_error())
{
result.type = Result.Type.DECODE_ERROR;
return;
return FindLongestMatchResult.decode_error();
}
bool lex_continue = false;
if (!decoded.is_eof())
if (decoded.is_eof())
{
/* We hit EOF. */
if (longest_match.length > 0)
{
/* We have a match, so use it. */
return longest_match;
}
else if (attempt_match.length != 0)
{
/* There is a partial match - error! */
return FindLongestMatchResult.unexpected_input(attempt_match.length);
}
else
{
/* Valid EOF return. */
return FindLongestMatchResult.eof();
}
}
else
{
auto transition_result = transition(current_state, decoded.code_point);
if (transition_result.found())
{
lex_continue = true;
attempt_match_info.length += decoded.code_point_length;
attempt_match.length += decoded.code_point_length;
if (decoded.code_point == '\n')
{
attempt_match_info.delta_row++;
attempt_match_info.delta_col = 0u;
attempt_match.delta_row++;
attempt_match.delta_col = 0u;
}
else
{
attempt_match_info.delta_col++;
attempt_match.delta_col++;
}
current_state = transition_result.destination();
if (states[current_state].accepts())
{
attempt_match_info.accepting_state = &states[current_state];
*match_info = attempt_match_info;
attempt_match.accepting_state = &states[current_state];
longest_match = attempt_match;
}
}
}
else if (attempt_match_info.length == 0u)
{
result.token = TOKEN___EOF;
result.type = Result.Type.TOKEN;
return;
}
if (!lex_continue)
{
return;
else if (longest_match.length > 0)
{
return longest_match;
}
else
{
return FindLongestMatchResult.unexpected_input(attempt_match.length + decoded.code_point_length);
}
}
}
}