Language Overview

File Extensions

By convention tscript is written in files using the extension .temu. TEMU also recognise .ts, and .tscript but that extension may clash with TypeScript.

Comments

tscript supports comments using either of the single line shell style (\#) or C style (//). The shell-style comments has been supported since TEMU 2 while the C-style comments were added in TEMU 3.

C-style comments are the preferred style since TEMU 3.

Commands and Command Methods

Commands are stand alone global commands. This was the only type of command in TEMU 2. TEMU 3 introduces command method, a command that is associated to a specific class and invoked on objects. The difference is that when interacting with objects using a traditional command, the object must be passed explicitly and the command must verify the type or compliance of the object to what the command expects, for a command method, this is not the case since they can only be invoked on objects that are already compliant to whatever rules are imposed on the object.

Meta Classes and Class Objects

In TEMU 3, tscript has been extended with meta classes and class objects. This primarily means that an object can be created using the class objects new method.

The new method does by default only take one argument (the object name) but classes can (in C or C++) customise the new method by querying for it by name from the class objects meta class and adding named required or optional arguments to the method reference.

Each registered class has a class object with the name of the class, in addition each class object is associated with a meta class, with the name @{CLASS_NAME}. In addition a root meta class responsible for constructing class and meta class pairs exists, this root class is named @MetaClass.

You should normally not be interacting with the meta classes directly, but they exist there to maintain property and methods registries for the class objects.

Variables

Variables are assigned as: foo=123 and referenced as ${foo} or $foo

Expressions

Tscript supports expressions. The operators supported depends on the type of the left and right hand sides.

Operator	Kind	Types
+	Binary	integer, float
-	Binary, Unary	integer, float
/	Binary	integer, float, paths
*	Binary	integer, float
./	Unary	paths
<<	Binary	integers
>>	Binary	integers
\|	Binary	integers
&	Binary	integers
~	Unary	integers
!	Unary	integers

Operator

Kind

Types

Binary

integer, float

Binary, Unary

integer, float

Binary

integer, float, paths

Binary

integer, float

Unary

paths

Binary

integers

Binary

integers

Binary

integers

Binary

integers

Unary

integers

Unary

integers

Conditional Statements

Tscript supports if-statements.

if expr {
  // statements
}

The conditional expression does not need to be parenthesised. However, the curly braces are mandatory.

Loops

Not yet implemented.

To anticipate the future implementation of loops, the keywords for, foreach and while have been reserved.

Commands and Functions

Commands are entities that can fail. A command halts execution of a script if running non interactivelly. Functions however are expressions and cannot fail.

Commands can be converted to expression values which will prevent non-interactive scripts from terminating by using the try keyword which converts the result of the command to a 1 for success and 0 for failure.

Built-in Functions

Function name

Function name
`defined(var)`	Return 1 if var is defined. 0 if not defined.

defined(var)

Return 1 if var is defined. 0 if not defined.

Command Definitions

It is possible to define commands both using the TEMU API and by defining commands in a tscript file.

defcmd mycmdname(a: string, b: path) {
  echo $a
  echo $b
}

mycmdname a=hello b=file.txt

A command can be failed using the raise statement.

A common use of a command would be to implement boot software emulation. The following example shows how a LEON3 processor can be booted:

defcmd boot(app: path) {
  if try load obj=mem0 file=${app} start-addr-var=startpc {
    if defined(startpc) {
      cpu0.setPC pc=$startpc
    }
    // Scaler reload register should be freq in MHz - 1
    grTimer0.scalerReload = cpu0.freq / 1e6 - 1

    // Prepare stack and frame pointer registers
    cpu0.setReg reg="%fp" value=0x40000000 + ram0.size - 4
    cpu0.setReg reg="%sp" value=0x40000000 + ram0.size - 4 - 92
  } else {
    raise "Failed to load file"
  }
}

Command Argument Types

The argument list is in the form of name type pairs, the argument name comes first, followed by a colon and then the typename. A number of types are supported at the moment:

int: integer type
real: double precision floating point
string: string type
path: string type (path indicates to auto completion to complete paths)
object: temu object type
iface: interface reference
prop: property reference

The arguments are available as scoped variables in the command body.

Exceptions

The raise statement raises an exception in a script and fails the current command. It takes a string as a parameter. This string will be printed out by the CLI as an error.

Exceptions can be caugth using the try expression. This expression converts the exception to a boolean.

   if try mem0.load file=foo.elf {
     // Success
   } else {
     raise "Could not load file!"
   }