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Convert Decoder.decode_code_point return type to a SumType

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This commit is contained in:
Josh Holtrop 2023-06-29 19:21:30 -04:00
parent 9895733a05
commit d466189982
1 changed files with 65 additions and 101 deletions
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166
assets/parser.d.erb
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@ -2,8 +2,8 @@
module <%= @grammar.modulename %>;
<% end %>
import std.stdio;
import std.sumtype;
<% @grammar.code_blocks.each do |code| %>
<%= code %>
@ -71,54 +71,23 @@ class <%= @classname %>
static class Decoder
{
struct Result
struct Success
{
enum Type
{
SUCCESS,
EOF,
DECODE_ERROR,
}
private Type type;
CodePoint code_point;
uint code_point_length;
static Result success(CodePoint code_point, uint code_point_length)
{
return Result(Type.SUCCESS, code_point, code_point_length);
}
bool is_success()
{
return type == Type.SUCCESS;
}
static Result eof()
{
return Result(Type.EOF);
}
bool is_eof()
{
return type == Type.EOF;
}
static Result decode_error()
{
return Result(Type.DECODE_ERROR);
}
bool is_decode_error()
{
return type == Type.DECODE_ERROR;
}
}
struct EOF {}
struct DecodeError {}
static Result decode_code_point(string input)
static SumType!(
Success,
EOF,
DecodeError)
decode_code_point(string input)
{
if (input.length == 0u)
{
return Result.eof();
return cast(ReturnType!decode_code_point)EOF();
}
char c = input[0];
CodePoint code_point;
@ -158,11 +127,11 @@ class <%= @classname %>
}
else
{
return Result.decode_error();
return cast(ReturnType!decode_code_point)DecodeError();
}
if (input.length <= following_bytes)
{
return Result.decode_error();
return cast(ReturnType!decode_code_point)DecodeError();
}
code_point_length = following_bytes + 1u;
for (size_t i = 0u; i < following_bytes; i++)
@ -170,12 +139,12 @@ class <%= @classname %>
char b = input[i + 1u];
if ((b & 0xC0u) != 0x80u)
{
return Result.decode_error();
return cast(ReturnType!decode_code_point)DecodeError();
}
code_point = (code_point << 6u) | (b & 0x3Fu);
}
}
return Result.success(code_point, code_point_length);
return cast(ReturnType!decode_code_point)Success(code_point, code_point_length);
}
}
@ -498,63 +467,58 @@ class <%= @classname %>
uint current_state = modes[m_mode].state_table_offset;
for (;;)
{
auto decoded = Decoder.decode_code_point(m_input[(m_input_position + attempt_match.length)..(m_input.length)]);
if (decoded.is_decode_error())
{
return FindLongestMatchResult.decode_error();
}
bool lex_continue = false;
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.length += decoded.code_point_length;
if (decoded.code_point == '\n')
{
attempt_match.delta_row++;
attempt_match.delta_col = 0u;
}
else
{
attempt_match.delta_col++;
}
current_state = transition_result.destination();
if (states[current_state].accepts())
{
attempt_match.accepting_state = &states[current_state];
longest_match = attempt_match;
}
}
else if (longest_match.length > 0)
{
return longest_match;
}
else
{
return FindLongestMatchResult.unexpected_input(attempt_match.length + decoded.code_point_length);
}
}
Decoder.decode_code_point(m_input[(m_input_position + attempt_match.length)..(m_input.length)]).match!(
(Decoder.DecodeError de) {return FindLongestMatchResult.decode_error();},
(Decoder.EOF e) {
/* 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();
}
},
(Decoder.Success decoded) {
auto transition_result = transition(current_state, decoded.code_point);
if (transition_result.found())
{
lex_continue = true;
attempt_match.length += decoded.code_point_length;
if (decoded.code_point == '\n')
{
attempt_match.delta_row++;
attempt_match.delta_col = 0u;
}
else
{
attempt_match.delta_col++;
}
current_state = transition_result.destination();
if (states[current_state].accepts())
{
attempt_match.accepting_state = &states[current_state];
longest_match = attempt_match;
}
}
else if (longest_match.length > 0)
{
return longest_match;
}
else
{
return FindLongestMatchResult.unexpected_input(attempt_match.length + decoded.code_point_length);
}
});
}
}