MATLAB Transpiler Limitations

Overview

The XDL MATLAB transpiler provides basic MATLAB compatibility but has several limitations. This document outlines what works and what doesn’t.

What Works ✅

Basic Operations

  • ✅ Scalar arithmetic: x = 5 + 3;
  • ✅ Variable assignment: a = 10;
  • ✅ Comments: % This is a comment
  • ✅ Basic operators: +, -, *, /, ^

Mathematical Functions

  • ✅ Trigonometric: sin(), cos(), tan(), asin(), acos(), atan()
  • ✅ Exponential/Log: exp(), sqrt()
  • ✅ Natural log: log() → transpiles to ALOG()
  • ✅ Base-10 log: log10() → transpiles to ALOG10()
  • ✅ Other: abs(), floor(), ceil(), round()

I/O Functions

  • ✅ Display output: disp(value) → transpiles to PRINT, value
  • ✅ Nested calls: disp(sin(0.5)) works correctly

Control Flow

  • ✅ IF/ELSE/ENDIF statements
  • ✅ FOR loops with ranges
  • ✅ WHILE loops
  • ✅ SWITCH/CASE statements
  • ✅ BREAK and CONTINUE statements

What Doesn’t Work ❌

Array/Matrix Operations

  • ❌ Array literals: [1, 2, 3, 4]
  • ❌ Matrix literals: [1 2; 3 4]
  • ❌ Element-wise operations on arrays: y = sin(x) where x is array
  • ❌ Array indexing with 1-based indexing
  • ❌ Colon operator: 1:10, 1:2:10

Array Generation Functions

  • ✅ linspace(start, end, n) → transpiles to LINSPACE()
  • ✅ logspace() → transpiles to LOGSPACE()
  • ⚠️ zeros(), ones() - Use REPLICATE(0, n) or DBLARR(n) instead
  • ✅ eye() → transpiles to IDENTITY()
  • ✅ rand(), randn() → transpiles to RANDOMU(), RANDOMN()

Plotting Features

  • ❌ figure - window management
  • ❌ hold on/off - multiple plots
  • ❌ xlabel, ylabel - axis labels (use XDL keywords instead)
  • ❌ title - plot title (use XDL keywords instead)
  • ❌ legend - plot legend
  • ❌ Line styles: 'b-', 'r--', etc.
  • ❌ Markers: '*', 'o', etc.
  • ❌ Plot properties: LineWidth, Marker, etc.

Advanced Features

  • ❌ User-defined functions
  • ❌ Anonymous functions/lambda: @(x) x^2
  • ❌ Cell arrays: {1, 2, 'three'}
  • ❌ Structures: struct.field
  • ❌ Classes and objects
  • ❌ String operations beyond basic strings
  • ❌ File I/O: fopen, fread, fwrite, etc.
  • ❌ fprintf with format strings

Control Flow Limitations

  • ✅ switch/case statements - Now supported
  • ❌ try/catch error handling - Not yet implemented
  • ✅ Complex FOR loop ranges: for i = 1:2:10 - Supported
  • ✅ while loops - Now supported
  • ✅ break, continue - Now supported

Workarounds

Instead of Array Literals

MATLAB:

x = [1, 2, 3, 4, 5];

XDL equivalent (write directly in XDL):

x = FINDGEN(5) + 1  ; Creates [1, 2, 3, 4, 5]

Instead of linspace

MATLAB:

x = linspace(0, 2*pi, 100);

XDL equivalent:

x = FINDGEN(100) * 2.0 * !PI / 99.0

Instead of MATLAB Plotting

MATLAB:

plot(x, y);
xlabel('X Axis');
ylabel('Y Axis');
title('My Plot');

XDL equivalent:

PLOT, x, y, title='My Plot', xtitle='X Axis', ytitle='Y Axis'

For Constants

MATLAB:

x = 2 * pi;

Use XDL system variables:

x = 2 * !PI

Available constants: !PI, !E, !DTOR (degrees to radians), !RTOD (radians to degrees)

For best results with MATLAB files:

  1. Simple Scalar Math: Use for basic calculations 
    a = 5;
b = 10;
c = sin(a) + cos(b);
disp(c);
  2. Individual Function Calls: Test mathematical functions 
    x = 0.5;
y = sin(x);
disp(y);

  3. Avoid Complex Features: Don’t use arrays, loops, or advanced plotting

  4. For Complex Work: Write directly in XDL
    • Full array support
    • Proper FOR loops
    • Complete plotting with keywords
    • All XDL features available

Migration Strategy

If you have MATLAB code to migrate:

  1. Simple scripts: May work with transpiler (test first)
  2. Array operations: Rewrite in XDL using FINDGEN, FLTARR, etc.
  3. Plotting: Rewrite using XDL PLOT with keywords
  4. Complex logic: Rewrite in XDL syntax

Examples That Work

See examples/matlab/ for working examples:

  • 01_simple_math.m - Basic arithmetic ✅
  • 02_trigonometry.m - Trig functions ✅
  • 03_simple_operations.m - sqrt, exp, log ✅
  • test_gui_output.m - Output capture ✅

Recent Improvements ✅

Enhancements completed in 2025:

  1. ✅ linspace() and logspace() functions
  2. ✅ Better FOR loop handling with ranges
  3. ✅ WHILE loop support
  4. ✅ SWITCH/CASE statement support
  5. ✅ BREAK and CONTINUE statements
  6. ✅ More complete function mapping (~80 functions)

Future Improvements

Planned enhancements:

  1. Array literal support: [1, 2, 3]
  2. try/catch error handling
  3. Plot style parsing (convert to XDL equivalents)
  4. Low-level file I/O (fopen, fread, fwrite)

Getting Help

If you encounter issues:

  1. Check this document for known limitations
  2. Try rewriting in XDL syntax
  3. See examples/xdl/ for XDL examples
  4. Consult docs/MATLAB_SUPPORT.md for supported features