new string function CStr, conversion to String using RightValue

Author: PetrPytelka

src/main/java/com/scriptbasic/utility/functions/StringFunctions.java

@@ -1,7 +1,9 @@
 package com.scriptbasic.utility.functions;
 
 import com.scriptbasic.api.BasicFunction;
+import com.scriptbasic.executors.rightvalues.BasicStringValue;
 import com.scriptbasic.interfaces.BasicRuntimeException;
+import com.scriptbasic.utility.RightValueUtility;
 
 /**
  * <p>
@@ -49,34 +51,56 @@ static public String chomp(final String s) {
         return s.replaceAll("\\n*$", "");
     }
 
+    /**
+     * Returns string for the argument.
+     * @param o argument to be converted
+     * @return string value
+     * @throws BasicRuntimeException failed to convert to string
+     */
+    @BasicFunction(classification = {com.scriptbasic.classification.String.class,
+            com.scriptbasic.classification.Utility.class})
+    static public String cstr(final Object o) throws BasicRuntimeException {
+        if (o == null) {
+            throw new BasicRuntimeException("Null cannot be converted to string");
+        }
+        if (o instanceof String) {
+            return (String) o;
+        }
+        return BasicStringValue.asString(RightValueUtility.createRightValue(o));
+    }
+
     /**
      * Trim the white spaces from the start of the string.
      *
-     * @param s the string to trim.
+     * @param o the string to trim.
      * @return the trimmed string
+     * @throws BasicRuntimeException if cannot convert to string
      */
     @BasicFunction(classification = {com.scriptbasic.classification.String.class,
             com.scriptbasic.classification.Utility.class})
-    static public String ltrim(final Object s) {
-        if(s==null) {
+    static public String ltrim(final Object o) throws BasicRuntimeException {
+        if(o==null) {
             return null;
         }
-        return s.toString().replaceAll("^\\s*", "");
+        final String s = cstr(o);
+        return s.replaceAll("^\\s*", "");
     }
 
     /**
      * Trim the white spaces from the end of the string.
      *
-     * @param s the string to trim
+     * @param o the string to trim
      * @return the trimmed string
+     * @throws BasicRuntimeException if cannot convert to string
      */
     @BasicFunction(classification = {com.scriptbasic.classification.String.class,
             com.scriptbasic.classification.Utility.class})
-    static public String rtrim(final Object s) {
-        if(s==null) {
+    static public String rtrim(final Object o) throws BasicRuntimeException {
+        if (o == null) {
             return null;
         }
-        return s.toString().replaceAll("\\s*$", "");
+        final String s = cstr(o);
+        return s.replaceAll("\\s*$", "");
     }
 
     /**
@@ -86,14 +110,15 @@ static public String rtrim(final Object s) {
      * @param o   parameter
      * @param len parameter
      * @return return value
+     * @throws BasicRuntimeException if cannot convert to string
      */
     @BasicFunction(classification = {com.scriptbasic.classification.String.class,
             com.scriptbasic.classification.Utility.class})
-    static public String left(final Object o, final int len) {
-        if(o==null) {
+    static public String left(final Object o, final int len) throws BasicRuntimeException {
+        if (o == null) {
             return null;
         }
-        String s = o.toString();
+        final String s = cstr(o);
         return s.length() > len ? s.substring(0, len) : s;
     }
 
@@ -113,10 +138,10 @@ static public String mid(final Object o, final int start, final int len) throws
         if (start < 1) {
             throw new BasicRuntimeException("Incorrect value in parameter start: " + start);
         }
-        if(o==null) {
+        if (o == null) {
             return null;
         }
-        String s = o.toString();
+        final String s = cstr(o);
         return s.substring(start - 1, start - 1 + len);
     }
 
@@ -127,14 +152,15 @@ static public String mid(final Object o, final int start, final int len) throws
      * @param o   parameter
      * @param len parameter
      * @return return value
+     * @throws BasicRuntimeException if cannot convert to string
      */
     @BasicFunction(classification = {com.scriptbasic.classification.String.class,
             com.scriptbasic.classification.Utility.class})
-    static public String right(final Object o, final int len) {
-        if(o==null) {
+    static public String right(final Object o, final int len) throws BasicRuntimeException {
+        if (o == null) {
             return null;
         }
-        String s = o.toString();
+        final String s = cstr(o);
         return s.length() > len ? s.substring(s.length() - len) : s;
     }
 
@@ -203,11 +229,12 @@ static public String lcase(final String s) {
     }
 
     @BasicFunction(classification = {com.scriptbasic.classification.String.class})
-    static public String trim(final Object s) {
-        if(s==null) {
+    static public String trim(final Object o) throws BasicRuntimeException {
+        if (o == null) {
             return null;
         }
-        return s.toString().trim();
+        final String s = cstr(o);
+        return s.trim();
     }
 
     /**

src/test/resources/com/scriptbasic/testprograms/TestStringFunctions.bas

@@ -10,7 +10,9 @@ assert("trim", trim(v)="1234")
 assert("rtrim", rtrim(v)=" 1234")
 
 ' Test null values
+assert("ltrim_with_null", IsNull(ltrim(xxx)))
 assert("trim_with_null", IsNull(trim(xxx)))
+assert("rtrim_with_null", IsNull(rtrim(xxx)))
 
 ' Test left, mid, right functions
 v = 1234