Merge pull request #12 from PetrPytelka/single_line_if_statement

Add support for single line statement (if .... then ... [else ...])

Author: verhas

src/main/java/com/scriptbasic/interfaces/LexicalElement.java

@@ -80,8 +80,6 @@ public interface LexicalElement extends SourceLocationBound {
     Boolean isSymbol(String lexeme);
 
     /**
-     * Return true if the lexical element is colon 
-     * 
      * @return true if the lexical element is colon
      */
     Boolean isStatementSeparator();

src/main/java/com/scriptbasic/interfaces/NestedStructureHouseKeeper.java

@@ -10,6 +10,24 @@
  * date June 8, 2012
  */
 public interface NestedStructureHouseKeeper {
+    
+    static public enum EndOfStatementResult {
+        /**
+         * End of statement was consumed. Other processors should not be called.
+         */
+        CONSUMED,
+        
+        /**
+         * End of statement was processed. Other processors should be notified.
+         */
+        PROCESSED
+    }
+
+    static public interface EndOfStatementProcessor {
+        
+        EndOfStatementResult consumeEndOfStatement() throws AnalysisException;
+        
+    }
 
     /**
      * Push a nested structure object on the housekeeping stack.
@@ -61,4 +79,18 @@ <T extends NestedStructure> T pop(Class<T> expectedClass)
      * @throws AnalysisException when there are some elements on the stack
      */
     void checkFinalState() throws AnalysisException;
+
+    /**
+     * Checks that there are no extra characters when the line analyzer 
+     * expects it has finished analyzing the statement. If there are
+     * some extra characters on the line then throws syntax error exception.
+     * Otherwise it simply steps the lexical analyzer iterator over the symbol.
+     *
+     * @throws AnalysisException when there are extra character on the actual line
+     */
+    void consumeEndOfStatement() throws AnalysisException;
+
+    void pushEndOfStatementProcessor(EndOfStatementProcessor endOfStatementProcessor);
+
+    EndOfStatementProcessor popEndOfStatementProcessor();
 }

src/main/java/com/scriptbasic/interfaces/SyntaxAnalyzer.java

@@ -1,5 +1,6 @@
 package com.scriptbasic.interfaces;
 
+import com.scriptbasic.spi.Command;
 
 /**
  * A syntax analyzer analyzes a program source using the result of the lexical
@@ -17,4 +18,11 @@ public interface SyntaxAnalyzer {
      */
     BuildableProgram analyze() throws AnalysisException;
 
+    /**
+     * Add command to the currently build program
+     * 
+     * @param command Command to be added to the current program
+     */
+    void addCommand(Command command);
+
 }

src/main/java/com/scriptbasic/syntax/AbstractNestedStructureHouseKeeper.java

@@ -4,7 +4,10 @@
 import com.scriptbasic.interfaces.*;
 import com.scriptbasic.log.Logger;
 import com.scriptbasic.log.LoggerFactory;
+import com.scriptbasic.utility.SyntaxExceptionUtility;
 
+import java.util.ArrayList;
+import java.util.List;
 import java.util.Stack;
 
 public abstract class AbstractNestedStructureHouseKeeper implements NestedStructureHouseKeeper {
@@ -17,6 +20,7 @@ public <T> boolean match(final Class<T> expectedClass) {
     private final Stack<Structure> stack = new Stack<>();
     private final LexicalAnalyzer analyzer;
     private boolean stackIsHealthy = true;
+    private final Stack<EndOfStatementProcessor> endOfStatementProcessors = new Stack<>();
 
     protected AbstractNestedStructureHouseKeeper(final LexicalAnalyzer analyzer) {
         this.analyzer = analyzer;
@@ -89,5 +93,47 @@ public void checkFinalState() throws AnalysisException {
         if (stack.size() > 0) {
             throw new BasicSyntaxException("There is at least one opened block on the stack. Block is not properly closed.");
         }
+        if (endOfStatementProcessors.size() > 0) {
+            throw new BasicSyntaxException("There is at least one unfinished statement.");
+        }
+    }
+    
+    @Override
+    public void consumeEndOfStatement() throws AnalysisException {
+ 
+        final var numOfProcessors = endOfStatementProcessors.size();
+        if(numOfProcessors>0) {
+            // Copy processors and revert order
+            // Note: Processors might be unregistered while iterating them
+            List<EndOfStatementProcessor> processors = new ArrayList<>(numOfProcessors);
+            final var iter = endOfStatementProcessors.listIterator(endOfStatementProcessors.size());
+            while(iter.hasPrevious()) {
+                processors.add(iter.previous());
+            }
+            // Run processors
+            for(final var processor: processors) {
+                final var result = processor.consumeEndOfStatement();
+                if(result==EndOfStatementResult.CONSUMED) {
+                    return;
+                }
+            }
+        }
+        
+        final var le = analyzer.get();
+        if (le != null && !(le.isLineTerminator() || le.isStatementSeparator())) {
+            SyntaxExceptionUtility.throwSyntaxException(
+                    "There are extra characters following the expression.", le);
+        }
+    }
+    
+    @Override
+    public void pushEndOfStatementProcessor(EndOfStatementProcessor endOfStatementProcessor)
+    {
+        endOfStatementProcessors.push(endOfStatementProcessor);
+    }
+    
+    @Override
+    public EndOfStatementProcessor popEndOfStatementProcessor() {
+        return endOfStatementProcessors.pop();
     }
 }

src/main/java/com/scriptbasic/syntax/BasicSyntaxAnalyzer.java

@@ -1,12 +1,17 @@
 package com.scriptbasic.syntax;
 
+import java.util.ArrayList;
+import java.util.List;
+
 import com.scriptbasic.interfaces.*;
+import com.scriptbasic.spi.Command;
 
 public final class BasicSyntaxAnalyzer implements SyntaxAnalyzer {
     private final LexicalAnalyzer lexicalAnalyzer;
     private final CommandFactory commandFactory;
     private final NestedStructureHouseKeeper nestedStructureHouseKeeper;
-    private LexicalElement lexicalElement;    
+    private LexicalElement lexicalElement;
+    private List<Command> additionalCommands;
 
     public BasicSyntaxAnalyzer(final LexicalAnalyzer lexicalAnalyzer, final CommandFactory commandFactory, 
                                final NestedStructureHouseKeeper nestedStructureHouseKeeper) {
@@ -50,12 +55,24 @@ public BuildableProgram analyze() throws AnalysisException {
                     buildableProgram.addCommand(newCommand);
                 }
             }
+            if(additionalCommands!=null) {
+                additionalCommands.forEach(buildableProgram::addCommand);
+                additionalCommands = null;
+            }
             this.lexicalElement = lexicalAnalyzer.peek();
         }
         nestedStructureHouseKeeper.checkFinalState();
         buildableProgram.postprocess();
         return buildableProgram;
     }
+    
+    @Override
+    public void addCommand(final Command command) {
+        if(additionalCommands==null) {
+            additionalCommands = new ArrayList<>();
+        }
+        additionalCommands.add(command);
+    }
 
     public static void consumeIgnoredLine(final LexicalAnalyzer lexicalAnalyzer, String lexString) throws AnalysisException {
         while (!lexString.equals("\n")) {

src/main/java/com/scriptbasic/syntax/commands/AbstractCommandAnalyzer.java

@@ -7,7 +7,6 @@
 import com.scriptbasic.spi.LeftValue;
 import com.scriptbasic.spi.LeftValueList;
 import com.scriptbasic.syntax.AbstractAnalyzer;
-import com.scriptbasic.utility.SyntaxExceptionUtility;
 
 public abstract class AbstractCommandAnalyzer extends AbstractAnalyzer<Command>
         implements CommandAnalyzer {
@@ -101,11 +100,6 @@ protected boolean isKeyWord(final String keyword) throws AnalysisException {
      * @throws AnalysisException when there are extra character on the actual line
      */
     protected void consumeEndOfStatement() throws AnalysisException {
-        final var le = ctx.lexicalAnalyzer.get();
-        if (le != null && !(le.isLineTerminator() || le.isStatementSeparator())) {
-            SyntaxExceptionUtility.throwSyntaxException(
-                    "There are extra characters following the expression after the '"
-                            + getName() + "' keyword", le);
-        }
+        ctx.nestedStructureHouseKeeper.consumeEndOfStatement();
     }
 }

src/main/java/com/scriptbasic/syntax/commands/AbstractCommandAnalyzerIfElseKind.java

@@ -21,9 +21,11 @@ protected void registerAndSwapNode(final AbstractCommandIfElseKind node)
         pushNode(node);
     }
 
-    protected void registerAndPopNode(final AbstractCommandIfElseKind node)
+    protected AbstractCommandIfElseKind registerAndPopNode(final AbstractCommandIfElseKind node)
             throws AnalysisException {
-        ctx.nestedStructureHouseKeeper.pop(AbstractCommandIfElseKind.class).setNext(node);
+        var command = ctx.nestedStructureHouseKeeper.pop(AbstractCommandIfElseKind.class);
+        command.setNext(node);
+        return command;
     }
 
 }

src/main/java/com/scriptbasic/syntax/commands/AbstractCommandAnalyzerIfKind.java

@@ -4,7 +4,6 @@
 import com.scriptbasic.interfaces.AnalysisException;
 import com.scriptbasic.interfaces.Expression;
 import com.scriptbasic.interfaces.ScriptBasicKeyWords;
-import com.scriptbasic.spi.Command;
 
 /**
  * @author Peter Verhas
@@ -16,22 +15,14 @@ public AbstractCommandAnalyzerIfKind(final Context ctx) {
         super(ctx);
     }
 
-    protected abstract Command createNode(Expression condition) throws AnalysisException;
-
-    /*
-     * (non-Javadoc)
-     *
-     * @see com.scriptbasic.interfaces.Analyzer#analyze()
+    /**
+     * Analyse expression and THEN keyword
+     * @return expression for IF statement
+     * @throws AnalysisException error when missing then keyword or failed to parse expression
      */
-    @Override
-    public Command analyze() throws AnalysisException {
-        return createNode(analizeLine());
-    }
-
-    protected Expression analizeLine() throws AnalysisException {
+    protected Expression analyzeCondition() throws AnalysisException {
         final var condition = analyzeExpression();
         assertKeyWord(ScriptBasicKeyWords.KEYWORD_THEN);
-        consumeEndOfStatement();
         return condition;
     }
 

src/main/java/com/scriptbasic/syntax/commands/CommandAnalyzerElse.java

@@ -1,8 +1,10 @@
 package com.scriptbasic.syntax.commands;
 
 import com.scriptbasic.context.Context;
+import com.scriptbasic.executors.commands.AbstractCommandIfElseKind;
 import com.scriptbasic.executors.commands.CommandElse;
 import com.scriptbasic.interfaces.AnalysisException;
+import com.scriptbasic.interfaces.BasicSyntaxException;
 import com.scriptbasic.spi.Command;
 
 public class CommandAnalyzerElse extends AbstractCommandAnalyzerIfElseKind {
@@ -14,8 +16,12 @@ public CommandAnalyzerElse(final Context ctx) {
     @Override
     public Command analyze() throws AnalysisException {
         final var node = new CommandElse();
+        AbstractCommandIfElseKind prevNode = registerAndPopNode(node);
+        if(prevNode instanceof CommandElse) {
+            throw new BasicSyntaxException("Multiple 'else' statements", ctx.lexicalAnalyzer.peek());
+        }
+        pushNode(node);
         consumeEndOfStatement();
-        registerAndSwapNode(node);
         return node;
     }
 

src/main/java/com/scriptbasic/syntax/commands/CommandAnalyzerElseIf.java

@@ -3,7 +3,6 @@
 import com.scriptbasic.context.Context;
 import com.scriptbasic.executors.commands.CommandElseIf;
 import com.scriptbasic.interfaces.AnalysisException;
-import com.scriptbasic.interfaces.Expression;
 import com.scriptbasic.spi.Command;
 
 /**
@@ -16,10 +15,15 @@ public CommandAnalyzerElseIf(final Context ctx) {
         super(ctx);
     }
 
-    protected Command createNode(final Expression condition) throws AnalysisException {
+    @Override
+    public Command analyze() throws AnalysisException {
+
+        final var condition = analyzeCondition();
+        
         final var node = new CommandElseIf();
         node.setCondition(condition);
         registerAndSwapNode(node);
+        consumeEndOfStatement();
         return node;
     }