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Noobeed is an interpreter, meaning that it reads one
statement at a time, then executes it, then goes on to the next statement and
repeats the same, over and over. At the Noobeed prompt, "->", the user
types a statement, once enter is pressed, Noobeed reads it and executes it
immediately. It is not until Noobeed finishes the current execution and
returns the prompt to the user that the user can enter another statement.
The same concept also works when running a program in Noobeed,i.e. it processes
the program statement line by line, one line at a time, from the top to the
bottom of the program.
There are 3 types of statement
-
command statement
-
expression statement
-
assignment statement
The following is to give an idea how the
interpreter works.
-
Each statement in a program is read into
Noobeed as a String, and is “left trim” and “right trim” before store into
memory. Therefore white spaces at the beginning and the end of a
statement play no roll at all.
-
Noobeed scans the whole statement. If
illegal characters are found, an error is reported. All possible legal
characters are listed at below.
-
Noobeed looks at the first word in the
statement. If it is a command, this is a command statement.
-
If not a command statement, Noobeed scans
for an equal sign, "=". If found, this is an assignment statement.
-
If not an assignment statement, it is an
expression statement.
Example
|
-> a =
Matrix(3,3) |
this is an assignment statement |
|
-> b = sin(deg(89.2563)) |
this is an
assignment statement |
|
-> 25 * (4.2+5.3) |
this is an expression statement |
|
-> set format "fix" |
this is a command statement |
The space or blank characters play no role in
the statement, for example:
|
->a = b.tsp () |
"tsp " is trimmed out as "tsp" |
|
->john = matrix() |
"john " is trimmed out as "john" |
Legal characters
|
letters
(upper case) |
A-Z |
|
letters
(lower case) |
a-z |
|
numbers |
0-9 |
|
underscore
sign |
_ |
|
all operator
signs |
+ - *
/ ^ % > < <> >= <= ! & | |
|
blank (white
space) |
ASCII code 32 |
|
decimal
point |
. ASCII code 46 |
|
comma |
,
ASCII code 44 |
|
semi colon |
;
ASCII code 32 |
|
parenthesis |
()
ASCII code 40, 41 |
|
bracket |
[] ASCII code 91, 93 |
|
double
quotation |
" ASCII code 34 |
Any characters that are NOT listed here are
illegal characters.
Precedence
The following lists the level of priority of
operator from highest to lowest. If same precedence, then they are done
from left to right.
|
Function() |
global,
class and L-functions (a constant Matrix created by using [ ] is also
treated as a function) |
|
! + - |
Unary (! is
from right to left) |
|
(
) |
expression in a parentheses |
|
^ |
power |
|
* / % |
multiply,
division, modulus (remainder) |
|
+ - |
plus, minus |
|
< <= >
>= |
less than,
less or equal to, greater than, greater than or equal to |
|
== <> |
equal to,
not equal to |
|
& |
and |
|
| |
or |
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