EVAL1
Synopsis
Evaluate an object, single pass
Stack Diagram
Input Stack | Output Stack | |||
---|---|---|---|---|
O | → | see list under Description | ||
Level 1 | → | Level n | … | Level 1 |
Type | Operator | |
Parallel list processing | Yes, but specific group is determined by the object being evaluated | |
Affected by flags | -70 | Global autosimplification rules |
-71 | Application of Group 1 autosimplification rules | |
-72 | Application of Group 2 autosimplification rules | |
-73 | Application of Group 3 autosimplification rules | |
-74 | Application of Group 4 autosimplification rules | |
-75 | Application of Group 5 autosimplification rules | |
-76 | Application of Group 6 autosimplification rules | |
-77 | Application of Group 7 autosimplification rules | |
-78 | Application of Group 8 autosimplification rules | |
-103 | Complex results |
Description
The EVAL1
command evaluates the object on the top level of the stack.
The effect of the evaluation and the resulting output depends on the type of object being evaluated, as summarized by the following list.
- Local Name:
EVAL1
recalls the content of the variable. - Global Name:
EVAL1
calls the content of a variable:- a Name is
EVAL
uated; - a Program is
EVAL
uated; - a Directory becomes the current directory;
- other objects which are not lists are put on the stack.
- Program:
EVAL1
enters each object in the program: - Symbolic expression:
EVAL1
enters each object in the expression:- a Name is
EVAL
uated; - a Keyword is
XEQ
ted; - other objects which are not lists are put on the stack.
- Other objects: if they are not lists
EVAL1
puts them on the stack. - List:
EVAL1
enters each object in the list:- any object is
EVAL
uated according above mentioned rules.
As a final step, EVAL1
will perform numerical simplification according to the status of flags from -70 to -78. If the final results
The main difference from EVAL
is that EVAL1
performs only one step of the process described above, allowing evaluation of recursive formulas that would otherwise yield a Circular reference
error.
Compatibility
This command is new in newRPL and does not exist in userRPL.
Usage
If the following command is executed
2: 'X+1' 1: 'X' …………………………………………………………………………………… STO
then the command
1: 'X' …………………………………………………………………………………… EVAL
would return a Circular reference
error.
Instead
1: 'X' …………………………………………………………………………………… EVAL1
will result in
1: 'X+1' ……………………………………………………………………………………
and further use of EVAL1
will return 'X+2'
, 'X+3'
, et cetera.
Related Commands
Operator | Short Description | |
---|---|---|
Evaluation operators: | ||
EVAL1 | Evaluate one level | NEW |
EVAL | Evaluate full depth | |
XEQ | Execute | NEW |
→NUM | Compute numeric result | |
Test operators: | ||
== | Equality test | |
≠ | Not equal test | |
< | Less than test | |
≤ | Less than or equal test | |
> | Greater than test | |
≥ | Greater than or equal test | |
CMP | Comparison test (<0 if A<B, 0 if A==B, >0 if A>B) | NEW |
SAME | Comparison test, true if objects are the same | |
ISTRUE | True test | NEW |
Logical operators: | ||
AND | Logical AND | |
OR | Logical OR | |
XOR | Logical XOR | |
NOT | Logical NOT | |
Mathematic operators: | ||
+ | Addition | |
- | Subtraction | |
* | Multiplication | |
/ | Division | |
^ | Power | |
XROOT | Root | |
INV | Inverse | |
NEG | Negate/change sign | |
ABS | Magnitude or absolute value |