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m2sci is a translation tool which allows to translate Matlab 4
m-files into Scilab function or scripts.
Usage
=====
To translate a Matlab M-file just enter the scilab instruction:
mfile2sci(file)
where file is a character string giving the path name of the M-file
mfile2sci will generate three files in the same directory
<function name>.sci : the scilab equivalent of the m_file
<function name>.cat : the scilab help file associated to the function
sci_<function name>.sci : the scilab function required to translate
the calls to this newly translated function. These
function may be improved "by hand".
When no specific translation is defined for a function mfile2sci uses
initial syntax as default translation. But the resulting function may
not work due to type conflict: in Matlab, logical comparisons generate
matrices with 0 or 1 entries, to have readable generated code we have
chosen to use Scilab boolean type to represent logical comparison
results.
In some cases M-files perform operations like (x>1).*a. Translation
of such things result in a run time error messages (unless users have
defined these operations using soft coded operations).
So far, there is no Scilab true equivalent for the Matlab "Global"
notion. But Scilab functions may "read" all variables defined in upper
contexts, so if Matlab global variables are not modified in the M-file
mfile2sci suppresses the global instruction. If variable is modified
mfile2sci replaces global action by a resume.
How it works
============
Scilab and Matlab syntax are very similar. So with some minor
modifications (performed by mfile2sci) of the original code
(comments,..) Scilab is able to get and interpret Matlab langage.
The interpreted code is used by the function macr2lst to generate a
Scilab list which contains the sequence of "operating codes" in
(reverse polish notation) and control flow structure.
Using this list it is then possible to generate a new "pretty print"
of the code where Matlab function and types are replaced by their
Scilab equivalents. This is done by the m2sci function. For each
Matlab function, m2sci calls a translating function named
sci_<Matlab_function_name>.
As some Matlab functions have different interpretations depending on
the fact that an argument is a matrix or a vector (max, min,ones,...)
mfile2sci tries to deduce variable types and dimensions while
translating the code. If it cannot determine type or dimension
translator replaces the call to the Matlab function by a call to a
special Scilab function (named mtlb_<function name>) written to
emulate it in all cases. User may use it directly or replace them by a
direct call to Scilab equivalent function if he knows the type or dimensions.
These functions are given in the distributed mtlb directory.
Each Matlab function (primitive or m-file) is translated by a Scilab
function named sci_<Matlab function name>. So far Just a part of
Matlab primitives functions have such a "translating function". See
"Translating function" below for guideline on how to write new
"translating functions"
When mfile2sci encounters a call to an "un-translated" function it
issues a warning message and re-write the original syntax. In such a
case you may either define the corresponding
sci_<Matlab_function_name> (see the already writen function as
examples), or translate the Matlab function using mfile2sci.
Known bugs
==========
1- m_files scripts are translated but sci_<Matlab function name>
replaces the call to the m_file by an exec of
an exec (.sce) file, the .sce file path may be incorrect.
2- eval function instructions passed as strings are not translated.
3- Syntaxes like 2.3i or 0.7j to form imaginary numbers produces an
error. replace them by 2.3*i ,0.7*j
4- most of plot function are not yet translated see below
5- globals are not translated
6- if, for, endded by the end of file produce an error, add the closing
end's
7- Loop variable of for clause is available afterwards if loops terminates
normally in matlab; it is cleared in Scilab generated code.
8- Translation of insertion syntax such as v(:)=x or v(i,:)=x produces a
run time error when v is an empty vector or matrix.
Use v=x or v(i,1:size(x,'*'))=x instead.
Translating function
====================
"Translating functions" are Scilab function with the following calling sequence:
[out_stk,txt,wt]=sci_<Matlab function name>()
These functions use the global variable stk, top, rhs, lhs
stk : is a list whose entries top+1-rhs:top contains the "formal
description" of the input arguments
rhs : is the number of calling input arguments
lhs : is the number of calling output arguments
out_stk : is a list whose entries 1:lhs contains the "formal
description" of the output arguments
txt : a character string vector written as it is in the translated
function
An argument "formal description" is a list with the following structure
list(def,type_expr,m,n,typevar)
def : is a character string which may contain
a Scilab expression like 'a+2*b-3*c(1)' or 'sin(2*%pi*A)' or 'A'
type_expr: is a character string which contains the "type" of the
expression stored in def:
- '2' : expression is a sum of terms
- '1' : expression is a product of factors
- '0' : expression is an atome like 'A', parenthesized
expression like '(a+2*b-3*c(1))' or 'sin(2*%pi*A)'
- '-1': must be set for each output formal description when
translated function is called with an lhs greater
than 1. In this case all def values must be set to
the same expression. (see sci_size.sci as an example)
- '-2': must be set for an output formal description when
corresponding lhs variable as already been set
throught txt. In this case corresponding def values
is ignored and may be set to ' '. See sci_eig.sci
as an example)
m : is a character string which contains the formal row size of
the matrix defined by def. If the size is not known m is
set to '?'.
n : is a character string which contains the formal column size of
the matrix defined by def. If the size is not known n is
set to '?'.
typevar : is a character string which contains the formal variable type of
the matrix defined by def. If the type is not known n is
set to '?'.
- '1' : matrix of numbers
- '4' : matrix of boolean
- '5' : sparse matrix of numbers
- '10': matrix of character strings
- '16': tlist
Usefull functions to write "translating functions"
==================================================
gettempvar : var=gettempvar(n)
returns in string var a "unique" variable name indexed
by integer n
isname : r=isname(str)
answers true if str represents a defined variable name
lhsvarsnames : [x1,x2,...]=lhsvarsnames()
returns in x1, x2,... the left hand side variable names
rhsargs : txt=rhsargs(args)
returns in string txt the input argument list formed by
the strings contained in vector args
rhsargs(['a','2*x',''foo'']) returns the string '(a,2*x,''foo'')'
lhsargs : txt=lhsargs(args)
returns in string txt the output argument list formed by
the strings contained in vector args
lhsargs(['a','b','c']) returns the string '[a,b,c]'
Non translated Matlab4 Built-in's
=================================
graphics
--------
axes.m clc.m contourc.m drawnow.m fill.m
patch.m fill3.m get.m getframe.m image.m
movie.m plot3.m rbbox.m semilogx.m semilogy.m
set.m surface.m eeset.m
gui
---
uicontrol.m uigetfile.m uimenu.m uiputfile.m
debug
------
dbclear.m dbcont.m dbdown.m dbquit.m dbstack.m
dbstatus.m dbstep.m dbstop.m dbtype.m dbup.m
c files
-------
fclose.m feof.m ferror.m fopen.m fread.m
fseek.m ftell.m fwrite.m
misc
----
global.m home.m isglobal.m lasterr.m which.m
sparsfun.m computer.m version.m dos.m echo.m
flops.m type.m what.m
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