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Reduce redundant escape code parsing #211

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This commit is contained in:
Jason Turner
2015-10-02 10:35:37 -06:00
parent 6a4647af43
commit 8d9dc2b0a3
1 changed files with 64 additions and 60 deletions
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124
include/chaiscript/language/chaiscript_parser.hpp
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@@ -949,6 +949,57 @@ namespace chaiscript
return false;
}
struct Char_Parser
{
bool is_escaped;
bool is_interpolated;
bool saw_interpolation_marker;
const bool interpolation_allowed;
Char_Parser(const bool t_interpolation_allowed)
: is_escaped(false),
is_interpolated(false),
saw_interpolation_marker(false),
interpolation_allowed(t_interpolation_allowed)
{
}
void parse(std::string &t_match, const char t_char, const int line, const int col, const std::string &filename) {
if (t_char == '\\') {
if (is_escaped) {
t_match.push_back('\\');
is_escaped = false;
} else {
is_escaped = true;
}
} else {
if (is_escaped) {
switch (t_char) {
case ('\'') : t_match.push_back('\''); break;
case ('\"') : t_match.push_back('\"'); break;
case ('?') : t_match.push_back('?'); break;
case ('a') : t_match.push_back('\a'); break;
case ('b') : t_match.push_back('\b'); break;
case ('f') : t_match.push_back('\f'); break;
case ('n') : t_match.push_back('\n'); break;
case ('r') : t_match.push_back('\r'); break;
case ('t') : t_match.push_back('\t'); break;
case ('v') : t_match.push_back('\v'); break;
case ('$') : t_match.push_back('$'); break;
default: throw exception::eval_error("Unknown escaped sequence in string", File_Position(line, col), filename);
}
} else if (interpolation_allowed && t_char == '$') {
saw_interpolation_marker = true;
} else {
t_match.push_back(t_char);
}
is_escaped = false;
}
}
};
/// Reads (and potentially captures) a quoted string from input. Translates escaped sequences.
bool Quoted_String(const bool t_capture = false) {
SkipWS();
@@ -960,19 +1011,19 @@ namespace chaiscript
if (Quoted_String_()) {
std::string match;
bool is_escaped = false;
bool is_interpolated = false;
bool saw_interpolation_marker = false;
Char_Parser cparser(true);
const auto prev_stack_top = m_match_stack.size();
auto s = start + 1, end = m_position - 1;
while (s != end) {
if (saw_interpolation_marker) {
if (cparser.saw_interpolation_marker) {
if (*s == '{') {
//We've found an interpolation point
if (is_interpolated) {
if (cparser.is_interpolated) {
//If we've seen previous interpolation, add on instead of making a new one
m_match_stack.push_back(make_node<eval::Quoted_String_AST_Node>(match, start.line, start.col));
@@ -993,7 +1044,7 @@ namespace chaiscript
}
if (*s == '}') {
is_interpolated = true;
cparser.is_interpolated = true;
++s;
const auto tostr_stack_top = m_match_stack.size();
@@ -1019,40 +1070,14 @@ namespace chaiscript
} else {
match.push_back('$');
}
saw_interpolation_marker = false;
cparser.saw_interpolation_marker = false;
} else {
if (*s == '\\') {
if (is_escaped) {
match.push_back('\\');
is_escaped = false;
} else {
is_escaped = true;
}
} else {
if (is_escaped) {
switch (*s) {
case ('b') : match.push_back('\b'); break;
case ('f') : match.push_back('\f'); break;
case ('n') : match.push_back('\n'); break;
case ('r') : match.push_back('\r'); break;
case ('t') : match.push_back('\t'); break;
case ('\'') : match.push_back('\''); break;
case ('\"') : match.push_back('\"'); break;
case ('$') : match.push_back('$'); break;
default: throw exception::eval_error("Unknown escaped sequence in string", File_Position(start.line, start.col), *m_filename);
}
} else if (*s == '$') {
saw_interpolation_marker = true;
} else {
match.push_back(*s);
}
is_escaped = false;
}
cparser.parse(match, *s, start.line, start.col, *m_filename);
++s;
}
}
if (is_interpolated) {
if (cparser.is_interpolated) {
m_match_stack.push_back(make_node<eval::Quoted_String_AST_Node>(match, start.line, start.col));
build_match<eval::Binary_Operator_AST_Node>(prev_stack_top, "+");
@@ -1104,33 +1129,12 @@ namespace chaiscript
const auto start = m_position;
if (Single_Quoted_String_()) {
std::string match;
bool is_escaped = false;
Char_Parser cparser(false);
for (auto s = start + 1, end = m_position - 1; s != end; ++s) {
if (*s == '\\') {
if (is_escaped) {
match.push_back('\\');
is_escaped = false;
} else {
is_escaped = true;
}
} else {
if (is_escaped) {
switch (*s) {
case ('b') : match.push_back('\b'); break;
case ('f') : match.push_back('\f'); break;
case ('n') : match.push_back('\n'); break;
case ('r') : match.push_back('\r'); break;
case ('t') : match.push_back('\t'); break;
case ('\'') : match.push_back('\''); break;
case ('\"') : match.push_back('\"'); break;
default: throw exception::eval_error("Unknown escaped sequence in string", File_Position(start.line, start.col), *m_filename);
}
} else {
match.push_back(*s);
}
is_escaped = false;
}
cparser.parse(match, *s, start.line, start.col, *m_filename);
}
m_match_stack.push_back(make_node<eval::Single_Quoted_String_AST_Node>(match, start.line, start.col));
return true;
}