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ValKmjolnir
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@@ -140,7 +140,7 @@ Reading this tutorial will not takes you over 15 minutes.
__If you have learnt C/C++/Javascript before, this will take less time.__
You could totally use it after reading this simple tutorial:
<details><summary><text style="font-weight:700;font-size:medium"> basic value type </text></summary>
<details><summary> basic value type </summary>
__`vm_none`__ is error type.
This type is used to interrupt the execution of virtual machine and will not be created by user program.
@@ -219,7 +219,7 @@ This type is often created by native-function of nasal. If want to define your o
</details>
<details><summary><text style="font-weight:700;font-size:medium"> operators </text></summary>
<details><summary> operators </summary>
Nasal has basic math operators `+` `-` `*` `/` and a special operator `~` that links two strings together.
@@ -255,7 +255,7 @@ a~='string';
</details>
<details><summary><text style="font-weight:700;font-size:medium"> definition </text></summary>
<details><summary> definition </summary>
```javascript
var a=1;
@@ -267,7 +267,7 @@ var (a,b,c)=(0,1,2);
</details>
<details><summary><text style="font-weight:700;font-size:medium"> multi-assignment </text></summary>
<details><summary> multi-assignment </summary>
The last one is often used to swap two variables.
@@ -279,7 +279,7 @@ The last one is often used to swap two variables.
</details>
<details><summary><text style="font-weight:700;font-size:medium"> conditional expression </text></summary>
<details><summary> conditional expression </summary>
In nasal there's a new key word `elsif`.
It has the same functions as `else if`.
@@ -298,7 +298,7 @@ if(1){
</details>
<details><summary><text style="font-weight:700;font-size:medium"> loop </text></summary>
<details><summary> loop </summary>
While loop and for loop is simalar to C/C++.
@@ -327,7 +327,7 @@ foreach(var i;elem)
</details>
<details><summary><text style="font-weight:700;font-size:medium"> subvec </text></summary>
<details><summary> subvec </summary>
Nasal provides this special syntax to help user generate a new vector by getting values by one index or getting values by indexes in a range from an old vector.
If there's only one index in the bracket, then we will get the value directly.
@@ -342,7 +342,7 @@ a[-1,1,0:2,0:,:3,:,nil:8,3:nil,nil:nil];
</details>
<details><summary><text style="font-weight:700;font-size:medium"> special function call </text></summary>
<details><summary> special function call </summary>
This is of great use but is not very efficient
(because hashmap use string as the key to compare).
@@ -353,7 +353,7 @@ f(x:0,y:nil,z:[]);
</details>
<details><summary><text style="font-weight:700;font-size:medium"> lambda </text></summary>
<details><summary> lambda </summary>
Also functions have this kind of use:
@@ -380,7 +380,7 @@ var fib=func(f){
</details>
<details><summary><text style="font-weight:700;font-size:medium"> closure </text></summary>
<details><summary> closure </summary>
Closure means you could get the variable that is not in the local scope of a function that you called.
Here is an example, result is `1`:
@@ -410,7 +410,7 @@ var student=func(n,a){
</details>
<details><summary><text style="font-weight:700;font-size:medium"> trait </text></summary>
<details><summary> trait </summary>
Also there's another way to OOP, that is `trait`.
@@ -492,7 +492,7 @@ If you want to use this trick to make the program running more efficiently, you
</details>
<details><summary><text style="font-weight:700;font-size:medium"> native functions and module import </text></summary>
<details><summary> native functions and module import </summary>
This part shows how we add native functions in this nasal interpreter.
If you are interested in this part, this may help you.
@@ -607,7 +607,7 @@ nas_ref builtin_keys(nas_ref* local,nasal_gc& gc)
</details>
<details><summary><text style="font-weight:700;font-size:medium"> modules(for lib developers) </text></summary>
<details><summary> modules(for lib developers) </summary>
If there is only one way to add your own functions into nasal,
that is really inconvenient.
@@ -743,17 +743,14 @@ foreach(i;[0,1,2,3])
print(i)
```
This program can run normally with output 0 1 2 3.
But take a look at the iterator 'i',
this symbol is defined in foreach without using keyword 'var'.
I think this design will make programmers filling confused.
This is ambiguous that programmers maybe difficult to find the 'i' is defined here.
Without 'var', programmers may think this 'i' is defined anywhere else.
This program can run normally.
But take a look at the iterator `i`,
it is defined in foreach without using keyword `var`.
I think this design will make programmers feeling confused that they maybe hard to find the `i` is defined here.
Without `var`, they may think this `i` is defined anywhere else.
So in this new interpreter i use a more strict syntax to force users to use 'var' to define iterator of forindex and foreach.
If you forget to add the keyword 'var',
and you haven't defined this symbol before,
you will get this:
So in this interpreter i use a more strict syntax to force users to use `var` to define iterator of forindex and foreach.
If you forget to add the keyword `var`, you will get this:
```javascript
[code] test.nas:2 undefined symbol "i".
@@ -764,17 +761,17 @@ foreach(i;[0,1,2,3])
### 2. default dynamic arguments not supported
In this new interpreter,
function doesn't put dynamic arguments into vector `arg` automatically.
In this interpreter,
function doesn't put dynamic args into vector `arg` by default.
So if you use `arg` without definition,
you'll get an error of `undefined symbol`.
## __Trace Back Info__
When the interpreter crashes,
When interpreter crashes,
it will print trace back information:
### 1. native function `die`
<details><summary>1. native function [die]</summary>
Function `die` is used to throw error and crash immediately.
@@ -803,7 +800,9 @@ vm stack(0x7fffcd21bc68<sp+80>, limit 10, total 12):
0x00000052 | nil |
```
### 2. stack overflow crash info
</details>
<details><summary>2. stack overflow crash info</summary>
Here is an example of stack overflow:
@@ -832,7 +831,9 @@ vm stack(0x7fffd3781d58<sp+80>, limit 10, total 8108):
0x00001ff2 | addr | 0x7fffd37a16e8
```
### 3. normal vm error crash info
</details>
<details><summary>3. normal vm error crash info</summary>
Error will be thrown if there's a fatal error when executing:
@@ -850,12 +851,12 @@ vm stack(0x7fffff539c28<sp+80>, limit 10, total 1):
0x00000050 | num | 0
```
### 4. detailed crash info
</details>
<details><summary>4. detailed crash info</summary>
Use command __`-d`__ or __`--detail`__ the trace back info will show more details:
<details><summary>show trace back info</summary>
```javascript
hello
[vm] error: error occurred this line