neat IF condtion implementation in a scripting language

I have a little helper class that generates a script, used later in my code, namely :

public class ScriptBuilder
{
public string Script { get; set; }
public ScriptBuilder NewLine(uint numberOfLines = 1)
{
if (numberOfLines == 0)
{
return this;
}
else
{
for (int i = 1; i <= numberOfLines; ++i)
{
Script += Environment.NewLine;
}
return this;
}
}
public ScriptBuilder WriteLine(string str = "")
{
if (str != "")
{
Script += str;
NewLine();
}
return this;
}
public ScriptBuilder(string line = "")
{
Script = line;
if (line != "")
{
NewLine();
}
}
public ScriptBuilder setLong(string longName, long x)
{
WriteLine("int " + longName + " " + x.ToString(System.Globalization.CultureInfo.InvariantCulture));
return this;
}

// + other set functions with different parameters/numbers of parameters
}

// ScriptBuilder is used like this :

ScriptBuilder scriptStringBuilder = new ScriptBuilder();
scriptStringBuilder
.WriteLine($"/!HEADSTART")
.WriteLine($"/! TYPE = {scriptType}")
.WriteLine($"/! NAME = {name}")
.WriteLine($"/! DESCRIPTION = {description}")
.WriteLine($"/!HEADEND")
/* the header is done now */
.NewLine(2);


It is pretty basic method chaining. I would like to implement IF and IF ELSE IF ELSE in this scripting language, but I don't see a really neat way for doing it.

IF

IF ELSE IF ELSE

For the IF I came up with the member function :

IF

public ScriptBuilder IF(bool condition, ScriptBuilder res)
{
if (condition)
{
return res;
}
else
{
return this;
}
}


that can be used as :

ScriptBuilder.IF(condition,
scriptStringBuilder
.setThis(...)
.setThat(...)
;
)


but I am not satisfied because

scriptStringBuilder.setThis(...).setThat(...);

scriptStringBuilder

IF ELSE IF ELSE

I could use delegates perhaps, like :

public delegate ScriptBuilder ScriptBuilderFunction(params object Parameters);
public ScriptBuilder IF(bool condition, ScriptBuilderFunction func)
{
// ...
}


but I don't even see how to implement that ...

Ideally, I would like to write :

scriptStringBuilder.
.setThis(...)
.setThat(...)
.IF(condition)
.THEN()
.setThis(...)
.doThat(...)
.ELSEIF(othercondition)
.makeThis(...)
.doThat(...)
.ENDIF()
.setThatNow(...)
;


MaxStringBuilder

IF

.setThis

ScriptBuilder

1 Answer
1

This is a very rough sketch of how you could implement this:

class Program
{
static void Main(string args)
{
var number = 999;

ScriptBuilder scriptStringBuilder = new ScriptBuilder();
var text = scriptStringBuilder
.WriteLine($"/!HEADSTART")
.WriteLine($"/! TYPE = abc")
.WriteLine($"/! NAME = name")
.WriteLine($"/!HEADEND")
.NewLine(2)
.IfCondition(number != 999, ifCondition => {
ifCondition.NewLine(1);
ifCondition.WriteLine("SUCCESS");
}, elseCondition => {
elseCondition.NewLine(1);
elseCondition.WriteLine("FAIL");
},
elseIf1 => elseIf1.ElseIfCondition(number > 1, h1 => h1.WriteLine("NUMBER IS BIGGER THAN 1")),
elseIf2 => elseIf2.ElseIfCondition(number > 2, h2 => h2.WriteLine("NUMBER IS BIGGER THAN 2")))
.Build();

Console.WriteLine(text);

Console.ReadKey();
}
}

public class ScriptBuilder : IElseIfConditionable
{
private string _script;

public ScriptBuilder NewLine(uint numberOfLines = 1)
{
if (numberOfLines == 0)
{
return this;
}
else
{
for (int i = 1; i <= numberOfLines; ++i)
{
_script += Environment.NewLine;
}
return this;
}
}
public ScriptBuilder WriteLine(string str = "")
{
if (str != "")
{
_script += str;
NewLine();
}
return this;
}
public ScriptBuilder(string line = "")
{
_script = line;
if (line != "")
{
NewLine();
}
}
public ScriptBuilder SetLong(string longName, long x)
{
WriteLine("int " + longName + " " + x.ToString(System.Globalization.CultureInfo.InvariantCulture));
return this;
}

public string Build()
{
return _script;
}

public ScriptBuilder IfCondition(bool condition, Action<ScriptBuilder> trueCondition, Action<ScriptBuilder> falseCondition, params Func<IElseIfConditionable, Tuple<ScriptBuilder, bool>> elseIfs)
{
if (condition)
{
trueCondition(this);
return this;
}

foreach (var elseIf in elseIfs)
{
if (elseIf(this).Item2)
{
return this;
}
}

if (!condition)
{
falseCondition(this);
}

return this;
}

public Tuple<ScriptBuilder, bool> ElseIfCondition(bool condition, Action<ScriptBuilder> trueCondition)
{
if (condition)
{
trueCondition(this);
}

return Tuple.Create(this, condition);
}
}

public interface IElseIfConditionable
{
Tuple<ScriptBuilder, bool> ElseIfCondition(bool condition, Action<ScriptBuilder> trueCondition);
}


This is equivalent of:

var s = new ScriptBuilder();
if (number != 999)
{
s.NewLine(1);
s.WriteLine("SUCCESS");
}
else if (number > 1)
{
s.WriteLine("NUMBER IS BIGGER THAN 1");
}
else if (number > 2)
{
s.WriteLine("NUMBER IS BIGGER THAN 2");
}
else
{
s.NewLine(1);
s.WriteLine("FAIL");
}


IElseIfConditionable, Tuple<ScriptBuilder, bool>

trueCondition

falseCondition

.IfCondition(s => s.ElseIfCondition(...))

IfCondition

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