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// It's often convenient to express recipes in a textual fashion.
:(scenario add_recipe)
recipe main [
1:integer <- copy 23:literal
]
+parse: instruction: 1
+parse: ingredient: {name: "23", type: 0}
+parse: product: {name: "1", type: 1}
:(code)
void run(string text) {
add_recipe(text);
}
void add_recipe(string form) {
istringstream in(form);
in >> std::noskipws;
string _recipe = next_word(in);
if (_recipe != "recipe")
raise << "top-level forms must be of the form 'recipe _name_ [ _instruction_ ... ]'\n";
string recipe_name = next_word(in);
if (recipe_name.empty())
raise << "empty recipe name in " << form << '\n';
int r = Recipe_number[recipe_name] = Next_recipe_number++;
if (next_word(in) != "[")
raise << "recipe body must begin with '['\n";
skip_newlines(in);
instruction curr;
while (next_instruction(in, &curr)) {
Recipe[r].step.push_back(curr);
}
}
bool next_instruction(istream& in, instruction* curr) {
curr->clear();
if (in.eof()) return false;
skip_whitespace(in); if (in.eof()) return false;
skip_newlines(in); if (in.eof()) return false;
vector<string> words;
while (in.peek() != '\n') {
skip_whitespace(in); if (in.eof()) return false;
string word = next_word(in); if (in.eof()) return false;
words.push_back(word);
skip_whitespace(in); if (in.eof()) return false;
}
skip_newlines(in); if (in.eof()) return false;
if (words.size() == 1 && *(words[0].end()-1) == ':') {
curr->is_label = true;
words[0].erase(words[0].end()-1);
curr->label = words[0];
trace("parse") << "label: " << curr->label;
return !in.eof();
}
vector<string>::iterator p = words.begin();
if (find(words.begin(), words.end(), "<-") != words.end()) {
for (; *p != "<-"; ++p) {
if (*p == ",") continue;
curr->products.push_back(reagent(*p));
}
++p; // skip <-
}
curr->operation = Recipe_number[*p]; ++p;
for (; p != words.end(); ++p) {
if (*p == ",") continue;
curr->ingredients.push_back(reagent(*p));
}
trace("parse") << "instruction: " << curr->operation;
for (vector<reagent>::iterator p = curr->ingredients.begin(); p != curr->ingredients.end(); ++p) {
trace("parse") << " ingredient: " << p->to_string();
}
for (vector<reagent>::iterator p = curr->products.begin(); p != curr->products.end(); ++p) {
trace("parse") << " product: " << p->to_string();
}
return !in.eof();
}
string next_word(istream& in) {
ostringstream out;
skip_whitespace(in);
slurp_word(in, out);
return out.str();
}
void slurp_word(istream& in, ostream& out) {
char c;
if (in.peek() == ',') {
in >> c;
out << c;
return;
}
while (in >> c) {
if (isspace(c) || c == ',') {
in.putback(c);
break;
}
out << c;
}
}
void skip_whitespace(istream& in) {
while (isspace(in.peek()) && in.peek() != '\n') {
in.get();
}
}
void skip_newlines(istream& in) {
while (in.peek() == '\n')
in.get();
}
void skip_comma(istream& in) {
skip_whitespace(in);
if (in.peek() == ',') in.get();
skip_whitespace(in);
}
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