rename examples test.cpp -> main.cpp (#20)

examples/simple/main.cpp

@@ -0,0 +1,27 @@
+#include <lars/parser/generator.h>
+
+int main() {
+  lars::ParserGenerator<float> g;
+
+  // Define grammar and evaluation rules
+  g.setSeparator(g["Whitespace"] << "[\t ]");
+  g["Sum"     ] << "Add | Subtract | Product";
+  g["Product" ] << "Multiply | Divide | Atomic";
+  g["Atomic"  ] << "Number | '(' Sum ')'";
+  g["Add"     ] << "Sum '+' Product"    >> [](auto e){ return e[0].evaluate() + e[1].evaluate(); };
+  g["Subtract"] << "Sum '-' Product"    >> [](auto e){ return e[0].evaluate() - e[1].evaluate(); };
+  g["Multiply"] << "Product '*' Atomic" >> [](auto e){ return e[0].evaluate() * e[1].evaluate(); };
+  g["Divide"  ] << "Product '/' Atomic" >> [](auto e){ return e[0].evaluate() / e[1].evaluate(); };
+  g["Number"  ] << "'-'? [0-9]+ ('.' [0-9]+)?" >> [](auto e){ return stof(e.string()); };
+  g.setStart(g["Sum"]);
+
+  // Execute a string
+  float result = g.run("1 + 2 * (3+4)/2 - 3");
+
+  // validate result
+  if (result == 5) {
+    return 0;
+  } else {
+    return 1;
+  }
+}