# Chained Boolean Operators

The idea is to avoid expression such as

if 0 <= i && i < array.length say "Index $i is ok!"

by allowing chaining of boolean expressions as follows

if 0 <= i < array.length say "Index $i is ok!"

## Syntactic Sugar for Chained Boolean Operators

The idea is for any infix operators `op1`

and `op2`

in an expression of the form

expr1 op1 expr2 op2 expr3

if `expr1 op1 expr2`

yields a bool result and ```
infix
op2
```

is not defined for bool but for the type of expr2 to convert this into:

tmp1 := expr1 tmp2 := expr2 (tmp1 op1 tmp2) && (tmp2 op2 expr3)

Longer chains should also be possible.

a < b < c < d < e < f < g

becomes

{ tmp1 := a; tmp2 := b; tmp1 < tmp2 } && { tmp3 := c; tmp2 < tmp3 } && { tmp4 := d; tmp3 < tmp4 } && { tmp5 := e; tmp4 < tmp5 } && { tmp6 := f; tmp5 < tmp6 } && (tmp6 < g)

## Syntactic Problems

The syntax of a call with actual generic arguments overlaps with the syntax of expressions

a < b > > c

is ambiguous and could be parsed as a call to `a`

giving the
actual generic argument `b`

and comparing the result of this call to `c`

(a < b >) > c

as well as

a < (b >) > c

which is equivalent to

a.infix <(b.postfix >).infix >(c)

In case an expression can be parsed as a generic argument, it should be interpreted as a generic argument.

## Other Languages

Python does something similar. How does this work in detail?