Added input, and read support for Arrays for the two issues

Author: krperry

README.md

@@ -27,6 +27,19 @@ $ python interpreter.py
 
 Although this started of as a personal project, it has been enhanced considerably by some other Github users. You can see them in the list of contributors! It's very much a group endeavour now.
 
+## Recent Updates
+
+### Array INPUT and READ Support
+The interpreter now supports reading data directly into array elements using both **INPUT** and **READ** statements:
+
+- **Array Elements as Targets**: Use syntax like `INPUT A(1), B(I+2)` and `READ N$(1), N$(2)`
+- **Expression Indices**: Support for complex expressions in array indices like `A(I*2+1)` 
+- **Mixed Data Types**: Read numeric and string data into appropriate array types
+- **Error Handling**: Proper SUBSCRIPT ERROR and OUT OF DATA error messages
+- **Specification Compliant**: Follows classic BASIC behavior for all edge cases
+
+See the comprehensive test program `examples/array_input_read_tests.bas` for demonstrations of all functionality.
+
 ## Operators
 
 A limited range of arithmetic expressions are provided. Addition and subtraction have the lowest precedence,
@@ -311,8 +324,38 @@ Hello Another Line of Data
 >
 ```
 
-It is a limitation of this BASIC dialect that it is not possible to assign constants directly to array variables
-within a **READ** statement, only simple variables.
+#### Array Support in READ
+
+The **READ** statement now supports reading data directly into array elements, using expressions for array indices:
+
+```
+> 10 DIM A(5)
+> 20 DIM N$(3)
+> 30 DATA 10, 20, 30, "Hello", "World"
+> 40 READ A(1), A(2), A(3), N$(1), N$(2)
+> 50 PRINT A(1); A(2); A(3); N$(1); N$(2)
+> RUN
+102030HelloWorld
+>
+```
+
+Array indices can be complex expressions including variables and arithmetic:
+
+```
+> 10 DIM B(10)
+> 20 I = 2
+> 30 DATA 100, 200
+> 40 READ B(I*3), B(I+4)
+> 50 PRINT "B(6)="; B(6)  REM Shows 200 (second value overwrites first)
+> RUN
+B(6)=200
+>
+```
+
+Proper error handling is provided:
+- **SUBSCRIPT ERROR**: When array indices are out of bounds or negative
+- **OUT OF DATA**: When there are no more DATA items to read
+- Index validation occurs BEFORE consuming DATA items
 
 ### Comments
 
@@ -720,6 +763,41 @@ Num, Str, Num: 22, hello!, 33
 >
 ```
 
+#### Array Support in INPUT
+
+The **INPUT** statement now supports inputting data directly into array elements:
+
+```
+> 10 DIM A(3)
+> 20 DIM N$(2)
+> 30 INPUT "Enter 3 numbers: "; A(1), A(2), A(3)
+> 40 INPUT "Enter 2 names: "; N$(1), N$(2)
+> 50 PRINT A(1); A(2); A(3); N$(1); N$(2)
+> RUN
+Enter 3 numbers: 5, 10, 15
+Enter 2 names: Alice, Bob
+51015AliceBob
+>
+```
+
+Array indices can use expressions with variables:
+
+```
+> 10 DIM B(10)
+> 20 I = 5
+> 30 INPUT "Enter value for B(I): "; B(I)
+> 40 PRINT "B(5)="; B(5)
+> RUN
+Enter value for B(I): 42
+B(5)=42
+>
+```
+
+Error handling includes:
+- **SUBSCRIPT ERROR**: When array indices are out of bounds
+- **"? REDO FROM START"**: When input types don't match array types
+- Index validation occurs BEFORE prompting for input
+
 A mismatch between the input value and input variable type will trigger an error, and the user will be asked
 to re-input the values again.
 
@@ -927,6 +1005,8 @@ and expanded by Don Woods.
 
 * *Pneuma.bas* - A brief 21st century take on the venerable text adventure.
 
+* *array_input_read_tests.bas* - A comprehensive test program that validates array INPUT and READ functionality, including expression indices, boundary conditions, error handling, and mixed data types. Demonstrates all the features of array element input and data reading.
+
 ## Informal grammar definition
 
 **ABS**(*numerical-expression*) - Calculates the absolute value of the result of *numerical-expression*