Programmable device providing visual feedback of balancing of opening and closing statements of programming structures and nesting level

1. A method for providing visual feedback of balancing of programming structure hierarchy in a program entered on a programmable device, comprising:

receiving at least two control structure opening statements, each having an associated control structure;

assigning a unique color to each of the at least two control structures;

displaying each control structure opening statement in the unique color assigned to the corresponding associated control structure;

receiving at least two control structure closing sequences; and

associating each control structure closing sequence with one of the control structures, respectively;

wherein the control structure opening statements and the control structure closing sequences start at a common starting position on an edge of a display of the programmable device.

2. The method of claim 1 , wherein the closing sequence is an explicit programming language control structure closing statement; and

further comprising displaying each closing statement in the unique color assigned to the control structure corresponding to each closing statement beginning at the same location with respect to the left edge.

3. The method of claim 1 , wherein the closing sequence is a special input sequence, the method further comprising in response to receiving the special input sequence, interpreting the special input sequence as a control structure closing sequence.

4. The method of claim 1 , further comprising:

assigning a nesting level to each control structure opening statement and closing sequence; and

wherein the step of assigning a unique representation to each control structure comprises assigning a same unique representation to control structures of the same nesting level.

5. The method of claim 4 , wherein at least one control structure further comprises a body, the method further comprising assigning a nesting level to the body that is one level deeper than the nesting level of a control structure opening statement and control structure closing sequence.

6. The method of claim 1 , further comprising:

determining whether for each control structure opening statement the program contains a corresponding control structure closing statement; and

upon determining that for each control structure opening statement the program contains a corresponding control structure closing statement, displaying a shaded background in the statements along a left line starting point adjacent the left edge of the display indicative of a nesting level of each line of the program displayed on the display.

7. The method of claim 6 , further comprising:

during interpretation of a program, using an indication of reduction of nesting level as indicative of closing of a program control structure.

8. The method of claim 7 , wherein the indication of reduction of nesting level is a reduction of number of initial shaded characters at a left line starting point adjacent the left edge of a line of the program shown on the display.

9. The method of claim 1 , further comprising retrieving a program from an instruction memory including receiving control structure opening statements and control structure closing sequences.

10. The method of claim 1 , further comprising receiving program statements entered by a user of an integrated programming environment of the programmable device and receiving program statements entered by a user of an integrated programming environment including receiving control structure opening statements and control structure closing sequences.

11. The method of claim 1 , wherein each control structure has a hierarchical level ranging from outermost to innermost and a scope associated therewith, and wherein associating each control structure closing statement with one of the control structures comprises:

determining all control structures that have a scope encompassing the closing statement; and

associating the closing statement with the control structure that has an innermost hierarchical level of the control structures that have a scope encompassing the control structure closing statement.

12. The method of claim 1 , wherein the program is a program written in BASIC programming language.

13. A programmable device, comprising:

a processor;

an input device connected to the processor;

a display connected to the processor and having a left edge;

a program memory connected to the processor; and

an instruction memory connected to the processor and storing instructions executable by the processor;

the instruction memory including an integrated programming environment comprising instructions which, when executed by the processor, cause the processor to:

receive at least two control structure opening statements, each having an associated control structure;

assign a unique color to each control structure of the at least two control structures;

concurrently display each control structure opening statement in the unique color assigned to the corresponding control structure;

receive at least two control structure closing sequences; and

associate each control structure closing sequence with one of the control structures;

wherein the control structure opening statements and the control structure closing sequences start at a common starting position on an edge of a display of the programmable device.

14. The programmable device of claim 13 wherein the unique representation is selected from a group consisting essentially of color, font, and frame style.

15. The programmable device of claim 13 , wherein the closing sequence is an explicit programming language control structure closing statement; and the instructions executed by the processor further comprising instructions to concurrently display each control structure closing statement in the unique color assigned to the corresponding control structure beginning at a determined location adjacent to or at the left edge.

16. The programmable device of claim 13 , wherein the closing sequence is a special input sequence, the instructions executed by the processor further comprising instructions to receive the special input sequence, interpreting the special input sequence as a control structure closing sequence.

17. The programmable device of claim 13 , the instructions executed by the processor further comprising instructions to assigning a nesting level to each control structure opening statement and closing sequence; and

wherein assigning a unique representation to each control structure comprises assigning a same unique representation to control structures of the same nesting level.

18. The programmable device of claim 13 , wherein the programmable device is a programmable graphing calculator.

19. The programmable device of claim 13 , wherein the programmable device is a handheld diagnostic device.

20. The programmable device of claim 13 , wherein the programmable device is a smartphone or tablet.