Nim - This repository contains the Nim compiler, Nim's stdlib, tools, and documentation. (mirror)

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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] ] +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 (ignores comments when scanning for matching // brackets) if it contains a newline at the start before any non-whitespace. 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 == '\\') { slurp_one_past_backslashes(in, out); 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 == '\\') { slurp_one_past_backslashes(in, out); 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 (starts_with(s, "[")) { if (*s.rbegin() != ']') return; // unbalanced bracket; handled elsewhere name = s; // delete [] delimiters name.erase(0, 1); strip_last(name); 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_text(r)) return emit_literal_string(r.name); :(code) bool is_literal_text(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); } void slurp_one_past_backslashes(istream& in, ostream& out) { // When you encounter a backslash, strip it out and pass through any // following run of backslashes. If we 'escaped' a single following // character, then the character '\' would be: // '\\' escaped once // '\\\\' escaped twice // '\\\\\\\\' escaped thrice (8 backslashes) // ..and so on. With our approach it'll be: // '\\' escaped once // '\\\' escaped twice // '\\\\' escaped thrice // This only works as long as backslashes aren't also overloaded to create // special characters. So Mu doesn't follow C's approach of overloading // backslashes both to escape quote characters and also as a notation for // unprintable characters like '\n'. while (has_data(in)) { char c = in.get(); out << c; if (c != '\\') break; } } :(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_twice) 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"} :(scenario multiple_unfinished_recipes) % Hide_errors = true; def f1 [ def f2 [ +error: unbalanced '['


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