Class parameter variable assignments

Question

I'm having a difficult time understanding why varone, vartwo, and varthree are getting "not found" errors: "not found: value "

// The following is being added to a list of type Foo
Foo(
    varone = "stringvalue",
    vartwo = "stringvalue",
    varthree = true
)

I'm defining Foo as:

class Foo(varone : String, vartwo : String, varthree : Boolean)
{

}

I thought in Scala would take my class parameters and make fields of them?

I'm coming from a C++ background and assignments in variable constructors seem strange, but that's what the example I'm following is hinting I do. I might just revert to giving Foo a constructor and making my assignments there, but I'd like to understand this way too.

Bruce Lowe · Accepted Answer · 2016-01-27 21:11:37Z

2

What you probably want is a case class

case class Foo(varone : String, vartwo : String, varthree : Boolean)

This will create all the variables for you as well as provide all the case class goodness of equals, hashes, immutability, pattern matching

Or if you don't want a case class:

class Foo(val varone : String, val vartwo : String, val varthree : Boolean)

If the field is a val, Scala will generate a getter method for it.

You can also declare it as a var, and Scala will generate both a getter and setter.

If the field doesn’t have a var / val, as in your example, Scala generates neither a getter nor setter method for the field.

edited Jan 27, 2016 at 21:11

answered Jan 27, 2016 at 21:06

Bruce Lowe

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Comments

Łukasz · Accepted Answer · 2016-01-27 21:12:12Z

1

You have to define the variables as 'val' for scala to make them as class members. Or you can use case classes.

Using 'val':

class Foo(val varone : String, val vartwo : String, val varthree : Boolean)

Using case class:

case class Foo(varone : String, vartwo : String, varthree : Boolean)

edited Jan 27, 2016 at 21:12

Łukasz

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answered Jan 27, 2016 at 21:04

James

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