From 9c831134ae20f2eb94c7104557c035ef935de7d6 Mon Sep 17 00:00:00 2001
From: Felix Queissner <felix@mq32.de>
Date: Mon, 10 Aug 2015 13:55:52 +0200
Subject: [PATCH] Adds method call support. Recursion is not supported, code is
 dieing by stack overflow :P

---
 trainscript/common.h      |  6 ++++++
 trainscript/file01.ts     | 25 +++++++++++++++++++++---
 trainscript/trainscript.y | 33 +++++++++++++++++++++++++++----
 trainscript/tsvm.cpp      |  2 +-
 trainscript/tsvm.hpp      | 41 +++++++++++++++++++++++++++++++++++++++
 5 files changed, 99 insertions(+), 8 deletions(-)

diff --git a/trainscript/common.h b/trainscript/common.h
index ed5f0d3..eb602bc 100644
--- a/trainscript/common.h
+++ b/trainscript/common.h
@@ -65,5 +65,11 @@ struct MethodDeclaration
 	MethodBody *body;
 };
 
+struct ExpressionList
+{
+	trainscript::Instruction *instruction;
+	ExpressionList *next;
+};
+
 // Variable declaration
 
diff --git a/trainscript/file01.ts b/trainscript/file01.ts
index 623353d..b404f18 100644
--- a/trainscript/file01.ts
+++ b/trainscript/file01.ts
@@ -1,10 +1,16 @@
 
 # Trainscript Test File
-VAR global : INT;
 VAR v1' : REAL;
 VAR v2' : REAL;
 
-PUB main(x : INT) → c : INT | m1:REAL, v1:REAL, m2:REAL, v2:REAL
+# Execute some stuff
+PUB main(x : INT) → c : INT
+	physics();
+	factorial(2);
+	42 → c;
+
+# Physics exercise with elastic collision
+PRI physics() | m1:REAL, v1:REAL, m2:REAL, v2:REAL
 	# Wagen 1
 	4.0 → m1;
 	1.2 → v1;
@@ -16,4 +22,17 @@ PUB main(x : INT) → c : INT | m1:REAL, v1:REAL, m2:REAL, v2:REAL
 	(((m1 - m2) * v1) + (2. * m2 * v2)) / (m1 + m2) → v1';
 	(((m2 - m1) * v2) + (2. * m1 * v1)) / (m1 + m2) → v2';
 
-	42 → c;
+# Recursive test
+PUB fibonacci(n : INT) → f : INT
+  #IF n = 0
+	0 → f;
+  #ELSEIF n = 1
+	1 → f;
+  #ELSE
+	fibonacci(n - 1) + fibonacci(n - 2) → f;
+
+PUB factorial(number : INT) → result : INT
+  #IF number <= 1
+	1 → result;
+  #ELSE
+	number * factorial(number - 1) → result;
diff --git a/trainscript/trainscript.y b/trainscript/trainscript.y
index c130a7a..cf9cca1 100644
--- a/trainscript/trainscript.y
+++ b/trainscript/trainscript.y
@@ -46,6 +46,7 @@ void yyerror(void *scanner, const char *s);
 	MethodHeader methodHeader;
 	trainscript::Instruction *instruction;
 	LocalVariable *local;
+	ExpressionList *expressions;
 }
 
 %token TAB
@@ -95,6 +96,8 @@ void yyerror(void *scanner, const char *s);
 %type <instruction> instruction
 %type <instruction> expression
 
+%type <expressions> expressionList
+
 %start input
 
 %left PLUS MINUS MULTIPLY DIVIDE MODULO RARROW
@@ -248,7 +251,15 @@ expression:
 |	REAL                                        { $$ = new ConstantExpression(mkvar($1)); }
 // |   TEXT                                     { $$ = new ConstantExpression(mkvar($1)); }
 |   IDENTIFIER                                  { $$ = new VariableExpression($1); }
-|   IDENTIFIER LBRACKET expressionList RBRACKET { $$ = nullptr; yyerror(nullptr, "missing instruction."); }
+|   IDENTIFIER LBRACKET expressionList RBRACKET {
+		auto *call = new MethodInvokeExpression($1);
+		auto *list = $3;
+		while(list) {
+			call->parameters.push_back(list->instruction);
+			list = list->next;
+		}
+		$$ = call;
+	}
 |   LBRACKET expression RBRACKET                { $$ = $2; }
 |   expression PLUS expression                  { $$ = new ArithmeticExpression<trainscript::ops::add>($1, $3); }
 |   expression MINUS expression                 { $$ = new ArithmeticExpression<trainscript::ops::subtract>($1, $3); }
@@ -259,9 +270,23 @@ expression:
 ;
 
 expressionList:
-	%empty
-|   expression
-|   expressionList COMMA expression
+	%empty { $$ = nullptr; }
+|   expression {
+		$$ = new ExpressionList();
+		$$->instruction = $1;
+		$$->next = nullptr;
+	}
+|   expressionList COMMA expression {
+		auto *list = new ExpressionList();
+		list->instruction = $3;
+		list->next = nullptr;
+
+		auto *it = $1;
+		while(it->next) { it = it->next; }
+		it->next = list;
+		$$ = $1;
+
+	}
 ;
 
 variableDeclaration:
diff --git a/trainscript/tsvm.cpp b/trainscript/tsvm.cpp
index 4712f89..82ad58c 100644
--- a/trainscript/tsvm.cpp
+++ b/trainscript/tsvm.cpp
@@ -74,7 +74,7 @@ namespace trainscript
 
 	Variable Method::invoke(std::vector<Variable> arguments)
 	{
-		LocalContext context;
+		LocalContext context(this->module);
 
 		for(auto var : this->module->variables)
 		{
diff --git a/trainscript/tsvm.hpp b/trainscript/tsvm.hpp
index bea879f..bb12bac 100644
--- a/trainscript/tsvm.hpp
+++ b/trainscript/tsvm.hpp
@@ -100,6 +100,15 @@ namespace trainscript
 			public std::map<std::string, Variable*>
 	{
 	public:
+		Module * const module = nullptr;
+
+		LocalContext(Module *mod) :
+			std::map<std::string, Variable*>(),
+			module(mod)
+		{
+
+		}
+
 		int depth;
 
 		LocalContext() : depth(0) { }
@@ -289,6 +298,38 @@ namespace trainscript
 		}
 	};
 
+	class MethodInvokeExpression :
+			public Instruction
+	{
+	public:
+		std::string methodName;
+		std::vector<Instruction*> parameters;
+
+		MethodInvokeExpression(std::string methodName) :
+			methodName(methodName)
+		{
+
+		}
+
+		Variable execute(LocalContext &context) const override
+		{
+			Method *method = context.module->method(this->methodName.c_str());
+			if(method == nullptr) {
+				if(verbose) printf("method %s not found!\n", this->methodName.c_str());
+				return Variable::Invalid;
+			}
+
+			if(verbose) context.depth++;
+			std::vector<Variable> vars(this->parameters.size());
+			for(int i =  0; i < vars.size(); i++) {
+				vars[i] = this->parameters.at(i)->execute(context);
+			}
+			if(verbose) context.depth--;
+
+			return method->invoke(vars);
+		}
+	};
+
 	template<Variable (*OP)(Variable, Variable)>
 	class ArithmeticExpression :
 			public Instruction