998 - convenient string initialization

3 files changed, 58 insertions, 2 deletions

diff --git a/cpp/.traces/new_string b/cpp/.traces/new_string
new file mode 100644
index 00000000..d9d75df4
--- /dev/null
+++ b/cpp/.traces/new_string
@@ -0,0 +1,22 @@
+parse/0: instruction: 24
+parse/0:   ingredient: {name: "abc def", value: 0, type: 0, properties: ["abc def": "literal-string"]}
+parse/0:   product: {name: "1", value: 0, type: 2-4-7, properties: ["1": "address":"array":"character"]}
+parse/0: instruction: 20
+parse/0:   ingredient: {name: "1", value: 0, type: 2-4-7, properties: ["1": "address":"array":"character", "deref": ]}
+parse/0:   ingredient: {name: "5", value: 0, type: 0, properties: ["5": "literal"]}
+parse/0:   product: {name: "2", value: 0, type: 7, properties: ["2": "character"]}
+new/0: abc def -> 0
+after-brace/0: recipe main
+after-brace/0: new ...
+after-brace/0: index ...
+run/0: instruction main/0
+mem/0: storing 1000 in location 1
+run/0: instruction main/1
+run/0: ingredient 0 is 1
+mem/0: location 1 is 1000
+run/0: ingredient 1 is 5
+run/0: address to copy is 1006
+run/0: its type is 7
+mem/0: location 1006 is 101
+run/0: product 0 is 101
+mem/0: storing 101 in location 2
diff --git a/cpp/.traces/string_literal b/cpp/.traces/string_literal
index b989b04a..3f7ff417 100644
--- a/cpp/.traces/string_literal
+++ b/cpp/.traces/string_literal
@@ -1,6 +1,6 @@
 parse/0: instruction: 24
 parse/0:   ingredient: {name: "abc def", value: 0, type: 0, properties: ["abc def": "literal-string"]}
-parse/0:   product: {name: "s", value: 0, type: 2-4-0, properties: ["s": "address":"array":"character"]}
+parse/0:   product: {name: "s", value: 0, type: 2-4-7, properties: ["s": "address":"array":"character"]}
 new/0: abc def -> 0
 name/0: assign s 1
 after-brace/0: recipe main
diff --git a/cpp/029string b/cpp/029string
index fd6b2824..209a1e7f 100644
--- a/cpp/029string
+++ b/cpp/029string
@@ -1,6 +1,13 @@
+//: Some instructions can take string literals for convenience.
+//:
+//: Instead of quotes, we'll use [] to delimit strings. That'll reduce the
+//: need for escaping. And we can also imagine that 'recipe' might one day
+//: itself be defined in mu, doing its own parsing.
+
+//: First extend the mu parser to support string literals.
 :(scenario "string_literal")
 recipe main [
-  s:address:array:character <- new [abc def]
+  1:address:array:character <- new [abc def]
 ]
 +parse:   ingredient: {name: "abc def", value: 0, type: 0, properties: ["abc def": "literal-string"]}
 
@@ -27,3 +34,30 @@ string slurp_quoted(istream& in) {
   }
   return out.str();
 }
+
+//: Next, extend 'new' to handle a string literal argument.
+:(scenario "new_string")
+recipe main [
+  1:address:array:character <- new [abc def]
+  2:character <- index 1:address:array:character/deref, 5:literal
+]
+# integer code for 'e'
++mem: storing 101 in location 2
+
+:(before "End Mu Types Initialization")
+Type_number["character"] = Next_type_number++;
+
+:(after "case NEW" following "Primitive Recipe Implementations")
+if (instructions[pc].ingredients[0].properties[0].second[0] == "literal-string") {
+  // allocate an array just large enough for it
+  vector<int> result;
+  result.push_back(Current_routine.alloc);
+  write_memory(instructions[pc].products[0], result);
+  // assume that all characters fit in a single location
+  Memory[Current_routine.alloc++] = instructions[0].name.size();
+  for (size_t i = 0; i < instructions[pc].ingredients[0].name.size(); ++i) {
+    Memory[Current_routine.alloc++] = instructions[pc].ingredients[0].name[i];
+  }
+  // mu strings are not null-terminated in memory
+  break;
+}