[FOray-commit] SF.net SVN: foray:[13823] trunk/foray/foray-ps/src/ma in/java/org/foray/ps/PsSystemDict4a.java

[<vic...@us...>]

Revision: 13823
          http://sourceforge.net/p/foray/code/13823
Author:   victormote
Date:     2025-06-06 11:59:19 +0000 (Fri, 06 Jun 2025)
Log Message:
-----------
Fix problems in currentfile() and readstring() related to casting of input streams.

Modified Paths:
--------------
    trunk/foray/foray-ps/src/main/java/org/foray/ps/PsSystemDict4a.java

Modified: trunk/foray/foray-ps/src/main/java/org/foray/ps/PsSystemDict4a.java
===================================================================
--- trunk/foray/foray-ps/src/main/java/org/foray/ps/PsSystemDict4a.java	2025-06-06 00:28:54 UTC (rev 13822)
+++ trunk/foray/foray-ps/src/main/java/org/foray/ps/PsSystemDict4a.java	2025-06-06 11:59:19 UTC (rev 13823)
@@ -1793,19 +1793,27 @@
      */
     private void currentfile() {
         /* The "currentfile" doc says this operator returns "the topmost file object on the execution stack."
-         * TODO: This method is therefore possibly wrong in two ways.
-         * 1. We understand "file" to mean "stream" which could include a PsString.
-         * 2. We are not sure what to do if the topmost item is not a "file" or other stream. Should the stack be
-         * traversed until one is found? Should non-file items on the stack be popped and then pushed to the operand
-         * stack? */
-        final PsObject psObject = getInterpreter().getExecutionStack().peek();
-        if (psObject instanceof PsInputStream) {
-            final PsInputStream psInputStream = (PsInputStream) psObject;
-            pushOperand(psInputStream);
-        } else {
-            /* Per "currentfile" doc, this never occurs during execution of ordinary user programs. */
-            pushOperand(new PsString(""));
+         * We have made two assumptions related to this.
+         * 1. We understand this to mean that there may be other things on the execution stack (such as procedures) that
+         *    should be ignored.
+         *    In other words, the stack needs to be traversed until a "file" is found.
+         *    We are pretty confident that this understanding is correct, practice showing that there are sometimes
+         *    procedures at the top of the stack when "currentfile" is called.
+         *    Since "currentfile" is frequently followed by "readstring" and a procedure could not be read from a
+         *    procedure for "readsting" purposes, we conclude that traversing the stack is correct.
+         * 2. We understand "file" to mean "stream" which could include a PsString.
+         *    We are much less confident that this is correct, but have found no practical evidence either way .*/
+        final PsExecutionStack executionStack = getInterpreter().getExecutionStack();
+        for (int index = 0; index < executionStack.size(); index ++) {
+            final PsObject psObject = executionStack.peek(index);
+            if (psObject instanceof PsInputStream) {
+                final PsInputStream psInputStream = (PsInputStream) psObject;
+                pushOperand(psInputStream);
+                return;
+            }
         }
+        /* Per "currentfile" doc, this never occurs during execution of ordinary user programs. */
+        pushOperand(new PsString(""));
     }
 
     /**
@@ -1920,17 +1928,17 @@
         @SuppressWarnings("resource")
         final PsString string = (PsString) object;
         object = popOperand(PsOperator.READSTRING);
-        if (! (object instanceof PsFile)) {
+        if (! (object instanceof PsInputStream)) {
             throw new PsOperatorException(PsError.TYPECHECK, PsOperator.READSTRING);
         }
         @SuppressWarnings("resource")
-        final PsFile file = (PsFile) object;
+        final PsInputStream file = (PsInputStream) object;
 
         final ByteArrayBuilder builder = new ByteArrayBuilder(string.getValue().length());
         builder.append(string.getValue());
 
         int charsRead = 0;
-        for (int i = 0; i < string.getValue().length() && file.isOpen(); i++) {
+        for (int i = 0; i < string.getValue().length(); i++) {
             try {
                 builder.setByteAt(i, (byte) file.read());
             } catch (final IOException e) {

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