【YarnSnipper】 unity剧情对话插件--语法

Yarn 语法

节点

定义

游戏中长长的剧本被分割成一段段的对话，Node节点就是用来分离故事为很多小的部分，这样使长的故事和分支容易管理。

• 每个节点之后有一个标题和主体。标题很重要，因为你的游戏使用节点标题告诉Yarn Snipper从哪个节点开始运行，以及跳转到哪个节点。游戏的标题不会显示给玩家。
• 节点标题可以以字母开始，可以包含字母、下划线和数字。节点标题中不可以含有如“a.”格式的字符。

规范

一个正确的节点应该如下所示：

title: Node_Title
---
Here are some lines!
Wow!
===

第一行是标题，用“:”进行分隔。

“---”是正文开始的标识，在此之后，你可以进行对话或者脚本逻辑的编写。
“===”是当前节点结束的标识，在这个节点之后，你可以写新的节点了。

---

This is a line of dialogue, without a character name.
Speaker: This is another line of dialogue said by a character called "Speaker".

如上面的语句第2行，如果在“:”之前有一个字符串，那么这个字符串将被标记成说这句话的人名，因此我们可以根据该人名进行语句的特殊效果。而第一行的意思就是没有指明谁说的这句话。

跳转

如果出现游戏中的选择，可以使用"->"字符串来标识该行是一个选择，如：

Companion: Hi there! What do you feel like doing today?

-> Player: I want to go swimming.
    Companion: Okay, let's go swimming.
-> Player: I'd prefer to go hiking.
    Companion: Cool, we'll go hiking then.
    
Player: Sounds good!

被"->"标记的两行对应的两种选择。在Player选择之后，Companion会立马做出回应，最后Player再做出回应。

---

嵌套选择

有时候，游戏中的选项之中又包含选项，于是我们就要用到嵌套选择，如下的对话：

Companion: Hi there! What do you feel like doing today?

-> Player: I want to go swimming.
    Companion: Okay, let's go swimming.
    Companion: Where do you want to swim?
    -> Player: The lake!
        Companion: Nice! It's a great day for it.
    -> Player: The swimming pool!
        Companion: Oh, awesome! I heard they installed a new slide.
-> Player: I'd prefer to go hiking.
    Companion: Cool, we'll go hiking then.
    
Player: Sounds good

逻辑也比较简单，就是抛出一个选项的时候，如果Player选择的是第一个，那么接着又会有新的选项问他去哪里游。这样写的话语句比较少，但是不够直观，因此以上对话还有下面的这样一种写法：

title: Start
---
Companion: Hi there! What do you feel like doing today?

-> Player: I want to go swimming.
    Companion: Okay, let's go swimming.
    <<jump Swimming>>
-> Player: I'd prefer to go hiking.
    Companion: Cool, we'll go hiking then.
    <<jump Hiking>>
===
title: Swimming
---
Companion: Where do you want to swim?
-> Player: The lake!
    Companion: Nice! It's a great day for it.
-> Player: The swimming pool!
    Companion: Oh, awesome! I heard they installed a new slide.

<<jump Done>>
===
title: Hiking
---
Companion: Have you got your hiking boots ready?
-> Player: Yes.
    Companion: Great, let's go!
-> Player: No.
    Companion: We can swing by your place and pick them up!

<<jump Done>>
===
title: Done
---
Player: Sounds good!
===

以上通过<<jump标题>>的形式跳转到另外一个节点去，这样的逻辑比较直观。

变量

变量类型

变量类型总共有3种

• Number：代表数字如 1，2.2，-200等
• String：字符串类型，比如"Hello World"
• Boolean:布尔类型，true 或false

变量用dollar字符表示，如：$hp

设置变量

• 通过<>来设置如：<<set $greeting to "Hello, Yarn!">>，意思就是将$greeting的变量设置为“Hello, Yarn!”
• 变量可以在之后进行更改，但是他的类型不可以更改，比如初始设置为数字类型，值是3，后面可以改成8，但是不可以将他从数字类型改为字符串类型。
• 还可以通过运算来赋值，比如：<<set $numberOfSidesInATriangle = 2 + 1>>，但只有同类型才可以。

在语句中使用变量

<<set $variableName to "a string value">>
The value of variableName is {$variableName}.

以上是在语句中使用变量的案例，输出的结果会是：The value of variableName is a string value.

条件控制

if 语句

if语句是条件语句，通常用来控制某条信息是否显示，以<<if 条件>>开始，<>进行结尾。如果if之后的天剑满足，则进入if和endif之间的语句，否则进入。

<<set $gold_amount to 5>>

Player: I'd like to buy a pie!

<<if $gold_amount < 10>>
    Baker: Well, you can't afford one!
<<endif>>

else if 和 else

每个else if语句后面会跟一个条件判断，如果之前的if或者任何的else if都不满足而当前的这条满足，则进入当前语句，如下：

Player: I'd like to buy a pie!

<<if $gold_amount < 10>>
    Baker: Well, you can't afford one!
<<elseif $gold_amount < 15>>
    Baker: You can almost afford one!
<<else>>
    Baker: Here you go!
<<endif>>

如果gold_amount是小于10，则显示：Well, you can't afford one! ；如果是小于15，则显示You can almost afford one! 即if满足，则不再判断后面的语句。

选项是否可用

条件选择在语句中出现，用来判断一个选项是否能被玩家选择，如下：

Guard: You're not allowed in!

-> Sure I am! The boss knows me! <<if $reputation > 10>>
-> Please?

如果第一个选项中的条件不满足时，则该选项不可以被选择。

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