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//: For convenience, some instructions will take literal arrays of characters
//: (text or strings).
//:
//: Instead of quotes, we'll use [] to delimit strings. That'll reduce the
//: need for escaping since we can support nested brackets. And we can also
//: imagine that 'recipe' might one day itself be defined in mu, doing its own
//: parsing.
:(scenarios load)
:(scenario string_literal)
def main [
1:address:array:character <- copy [abc def] # copy can't really take a string
]
+parse: ingredient: {"abc def": "literal-string"}
:(scenario string_literal_with_colons)
def main [
1:address:array:character <- copy [abc:def/ghi]
]
+parse: ingredient: {"abc:def/ghi": "literal-string"}
:(before "End Mu Types Initialization")
put(Type_ordinal, "literal-string", 0);
:(before "End next_word Special-cases")
if (in.peek() == '[') {
string result = slurp_quoted(in);
skip_whitespace_and_comments_but_not_newline(in);
return result;
}
:(code)
string slurp_quoted(istream& in) {
ostringstream out;
assert(has_data(in)); assert(in.peek() == '['); out << static_cast<char>(in.get()); // slurp the '['
if (is_code_string(in, out))
slurp_quoted_comment_aware(in, out);
else
slurp_quoted_comment_oblivious(in, out);
return out.str();
}
// A string is a code string if it contains a newline before any non-whitespace
// todo: support comments before the newline. But that gets messy.
bool is_code_string(istream& in, ostream& out) {
while (has_data(in)) {
char c = in.get();
if (!isspace(c)) {
in.putback(c);
return false;
}
out << c;
if (c == '\n') {
return true;
}
}
return false;
}
// Read a regular string. Regular strings can only contain other regular
// strings.
void slurp_quoted_comment_oblivious(istream& in, ostream& out) {
int brace_depth = 1;
while (has_data(in)) {
char c = in.get();
if (c == '\\') {
out << static_cast<char>(in.get());
continue;
}
out << c;
if (c == '[') ++brace_depth;
if (c == ']') --brace_depth;
if (brace_depth == 0) break;
}
if (!has_data(in) && brace_depth > 0) {
raise << "unbalanced '['\n" << end();
out.clear();
}
}
// Read a code string. Code strings can contain either code or regular strings.
void slurp_quoted_comment_aware(istream& in, ostream& out) {
char c;
while (in >> c) {
if (c == '\\') {
out << static_cast<char>(in.get());
continue;
}
if (c == '#') {
out << c;
while (has_data(in) && in.peek() != '\n') out << static_cast<char>(in.get());
continue;
}
if (c == '[') {
in.putback(c);
// recurse
out << slurp_quoted(in);
continue;
}
out << c;
if (c == ']') return;
}
raise << "unbalanced '['\n" << end();
out.clear();
}
:(after "Parsing reagent(string s)")
if (s.at(0) == '[') {
assert(*s.rbegin() == ']');
// delete [] delimiters
s.erase(0, 1);
strip_last(s);
name = s;
type = new type_tree("literal-string", 0);
return;
}
//: Unlike other reagents, escape newlines in literal strings to make them
//: more friendly to trace().
:(after "string to_string(const reagent& r)")
if (is_literal_string(r))
return emit_literal_string(r.name);
:(code)
bool is_literal_string(const reagent& x) {
return x.type && x.type->name == "literal-string";
}
string emit_literal_string(string name) {
size_t pos = 0;
while (pos != string::npos)
pos = replace(name, "\n", "\\n", pos);
return "{\""+name+"\": \"literal-string\"}";
}
size_t replace(string& str, const string& from, const string& to, size_t n) {
size_t result = str.find(from, n);
if (result != string::npos)
str.replace(result, from.length(), to);
return result;
}
void strip_last(string& s) {
if (!s.empty()) s.erase(SIZE(s)-1);
}
:(scenario string_literal_nested)
def main [
1:address:array:character <- copy [abc [def]]
]
+parse: ingredient: {"abc [def]": "literal-string"}
:(scenario string_literal_escaped)
def main [
1:address:array:character <- copy [abc \[def]
]
+parse: ingredient: {"abc [def": "literal-string"}
:(scenario string_literal_escaped_comment_aware)
def main [
1:address:array:character <- copy [
abc \\\[def]
]
+parse: ingredient: {"\nabc \[def": "literal-string"}
:(scenario string_literal_and_comment)
def main [
1:address:array:character <- copy [abc] # comment
]
+parse: --- defining main
+parse: instruction: copy
+parse: number of ingredients: 1
+parse: ingredient: {"abc": "literal-string"}
+parse: product: {1: ("address" "array" "character")}
:(scenario string_literal_escapes_newlines_in_trace)
def main [
copy [abc
def]
]
+parse: ingredient: {"abc\ndef": "literal-string"}
:(scenario string_literal_can_skip_past_comments)
def main [
copy [
# ']' inside comment
bar
]
]
+parse: ingredient: {"\n # ']' inside comment\n bar\n ": "literal-string"}
:(scenario string_literal_empty)
def main [
copy []
]
+parse: ingredient: {"": "literal-string"}
|