v0.9 (#46)

* always get properties

* update examples

* update travis

* add doctest example

* update example runner

examples/parser/CMakeLists.txt

@@ -0,0 +1,15 @@
+cmake_minimum_required(VERSION 3.5 FATAL_ERROR)
+
+# add dependencies
+include(../../cmake/CPM.cmake)
+
+CPMAddPackage(
+  NAME LarsParser
+  GIT_REPOSITORY https://github.com/TheLartians/Parser.git
+  VERSION 1.7
+)
+
+# add executable
+add_executable(calculator main.cpp)
+set_target_properties(calculator PROPERTIES CXX_STANDARD 17)
+target_link_libraries(calculator LarsParser)

examples/parser/main.cpp

@@ -0,0 +1,57 @@
+#include <iostream>
+#include <unordered_map>
+#include <cmath>
+
+#include <lars/parser/generator.h>
+
+int main() {
+  using namespace std;
+  using VariableMap = unordered_map<string, float>;
+  
+  lars::ParserGenerator<float, VariableMap &> calculator;
+  
+  auto &g = calculator;
+  g.setSeparator(g["Whitespace"] << "[\t ]");
+
+  g["Expression"] << "Set | Sum";
+  g["Set"       ] << "Name '=' Sum" >> [](auto e, auto &v){ return v[e[0].string()] = e[1].evaluate(v); };
+  g["Sum"       ] << "Add | Subtract | Product";
+  g["Product"   ] << "Multiply | Divide | Exponent";
+  g["Exponent"  ] << "Power | Atomic";
+  g["Atomic"    ] << "Number | Brackets | Variable";
+  g["Brackets"  ] << "'(' Sum ')'";
+  g["Add"       ] << "Sum '+' Product"       >> [](auto e, auto &v){ return e[0].evaluate(v) + e[1].evaluate(v); };
+  g["Subtract"  ] << "Sum '-' Product"       >> [](auto e, auto &v){ return e[0].evaluate(v) - e[1].evaluate(v); };
+  g["Multiply"  ] << "Product '*' Exponent"  >> [](auto e, auto &v){ return e[0].evaluate(v) * e[1].evaluate(v); };
+  g["Divide"    ] << "Product '/' Exponent"  >> [](auto e, auto &v){ return e[0].evaluate(v) / e[1].evaluate(v); };
+  g["Power"     ] << "Atomic ('^' Exponent)" >> [](auto e, auto &v){ return pow(e[0].evaluate(v), e[1].evaluate(v)); };
+  g["Variable"  ] << "Name" >> [](auto e, auto &v){ return v[e[0].string()]; };
+  g["Name"      ] << "[a-zA-Z] [a-zA-Z0-9]*";
+  g["Number"    ] << "'-'? [0-9]+ ('.' [0-9]+)?" >> [](auto e, auto &){ return stod(e.string()); };
+
+  g.setStart(g["Expression"]);
+
+  cout << "Enter an expression to be evaluated or 'quit' to exit.\n";
+
+  VariableMap variables;
+
+  while (true) {
+    string str;
+    cout << "> ";
+    getline(cin,str);
+    if(str == "q" || str == "quit"){ break; }
+    try {
+      auto result = calculator.run(str, variables);
+      cout << str << " = " << result << endl;
+    } catch (lars::SyntaxError &error) {
+      auto syntax = error.syntax;
+      cout << "  ";
+      cout << string(syntax->begin, ' ');
+      cout << string(syntax->length(), '~');
+      cout << "^\n";
+      cout << "  " << "Syntax error while parsing " << syntax->rule->name << endl;
+    }
+  }
+
+  return 0;
+}