Resolves #14 - Load now keeps track of directories

fitnesse/FitNesseRoot/LispInterpreter/ExternalFunctionUnitTests.wiki

@@ -4,6 +4,4 @@ Test
 Unit tests for the dlambda special function.
 
 | script           | lisp interpreter fixture                |
-| show  | evaluate | (load "lisp/unit-test.lisp")            |
-| show  | evaluate | (load "lisp/dlambda.lisp")              |
 | show  | evaluate | (load "lisp/dlambda-test.lisp")         |

fitnesse/FitNesseRoot/LispInterpreter/ObjectComposition.wiki

@@ -4,7 +4,6 @@ Test
 Shows object composition, a default method, and two different ways of referencing objects.
 
 | script           | lisp interpreter fixture                |
-| show  | evaluate | (load "lisp/dlambda.lisp")              |
 | show  | evaluate | (load "lisp/fruit-counter.lisp")        |
 | check | evaluate | (my-counter :inc-apples)                | 1    |
 | check | evaluate | (my-counter :inc-apples)                | 2    |

fitnesse/FitNesseRoot/RecentChanges.wiki

@@ -1,6 +1,7 @@
+|LispInterpreter.ExternalFunctionUnitTests||12:36:10 Fri, Mar 03, 2017|
+|LispInterpreter.ObjectComposition||12:36:01 Fri, Mar 03, 2017|
 |LispInterpreter.DlambdaUnitTests||10:16:42 Fri, Mar 03, 2017|
 |LispInterpreter.dlambda||10:12:59 Fri, Mar 03, 2017|
-|LispInterpreter.ObjectComposition||09:05:15 Fri, Mar 03, 2017|
 |LispInterpreter||09:04:51 Fri, Mar 03, 2017|
 |LispInterpreter.LexicalClosures||16:31:40 Thu, Mar 02, 2017|
 |LispInterpreter.LexicalClosure||16:26:49 Thu, Mar 02, 2017|

src/function/builtin/LOAD.java

@@ -6,6 +6,7 @@ import static sexpression.Symbol.T;
 
 import java.io.*;
 import java.text.MessageFormat;
+import java.util.Stack;
 
 import environment.RuntimeEnvironment;
 import error.*;
@@ -18,12 +19,14 @@ public class LOAD extends LispFunction {
 
     private ArgumentValidator argumentValidator;
     private ErrorManager errorManager;
+    private Stack<String> pathPrefixes;
 
     public LOAD() {
         this.argumentValidator = new ArgumentValidator("LOAD");
         this.argumentValidator.setExactNumberOfArguments(1);
         this.argumentValidator.setEveryArgumentExpectedType(LispString.class);
         this.errorManager = RuntimeEnvironment.getInstance().getErrorManager();
+        this.pathPrefixes = new Stack<>();
     }
 
     public SExpression call(Cons argumentList) {
@@ -40,13 +43,18 @@ public class LOAD extends LispFunction {
     }
 
     private SExpression processFile(String fileName) {
-        boolean wasSuccessful = false;
-        LispParser parser = attemptToCreateParserOnFile(fileName);
+        boolean isSuccessful = false;
+        String prefixedFileName = prefixFileNameIfNecessary(fileName);
+        LispParser parser = attemptToCreateParserOnFile(prefixedFileName);
 
         if (parser != null)
-            wasSuccessful = isSuccessfulEvaluation(parser);
+            isSuccessful = isSuccessfulEvaluationWithPathPrefix(prefixedFileName, parser);
 
-        return wasSuccessful ? T : NIL;
+        return isSuccessful ? T : NIL;
+    }
+
+    private String prefixFileNameIfNecessary(String fileName) {
+        return pathPrefixes.empty() ? fileName : pathPrefixes.peek() + fileName;
     }
 
     private LispParser attemptToCreateParserOnFile(String fileName) {
@@ -61,6 +69,18 @@ public class LOAD extends LispFunction {
         return parser;
     }
 
+    private boolean isSuccessfulEvaluationWithPathPrefix(String prefixedFileName, LispParser parser) {
+        pathPrefixes.push(getPathPrefix(prefixedFileName));
+        boolean isSuccessful = isSuccessfulEvaluation(parser);
+        pathPrefixes.pop();
+
+        return isSuccessful;
+    }
+
+    private String getPathPrefix(String fileName) {
+        return fileName.substring(0, fileName.lastIndexOf(File.separator) + 1);
+    }
+
     private boolean isSuccessfulEvaluation(LispParser parser) {
         while (!parser.isEof()) {
             try {

test/function/builtin/LOADTester.java

@@ -33,7 +33,7 @@ public class LOADTester {
     }
 
     private void assertNothingPrinted() {
-        assertTrue(outputStream.toByteArray().length == 0);
+        assertTrue(errorOutputStream.toByteArray().length == 0);
         assertTrue(outputStream.toByteArray().length == 0);
     }
 
@@ -74,6 +74,22 @@ public class LOADTester {
         assertWarningMessagePrinted();
     }
 
+    @Test
+    public void nestedLoadsInTheSameDirectory() {
+        String input = "(load \"test/function/builtin/test-files/nested/nested.lisp\")";
+
+        assertT(evaluateString(input));
+        assertNothingPrinted();
+    }
+
+    @Test
+    public void nestedLoadsInDifferentDirectories() {
+        String input = "(load \"test/function/builtin/test-files/nested/one/load-one.lisp\")";
+
+        assertT(evaluateString(input));
+        assertNothingPrinted();
+    }
+
     @Test(expected = BadArgumentTypeException.class)
     public void loadWithBadArgumentType() {
         evaluateString("(load '1)");

test/function/builtin/test-files/nested/included.lisp

@@ -0,0 +1 @@
+"included"

test/function/builtin/test-files/nested/nested.lisp

@@ -0,0 +1 @@
+(load "included.lisp")

test/function/builtin/test-files/nested/one/load-one.lisp

@@ -0,0 +1 @@
+(load "two/three/load-three.lisp")

test/function/builtin/test-files/nested/one/two/load-two.lisp

@@ -0,0 +1 @@
+(load "../../nested.lisp")

test/function/builtin/test-files/nested/one/two/three/load-three.lisp

@@ -0,0 +1 @@
+(load "../load-two.lisp")