symbol

symbols

In wasp, data and code have the same syntax.

The main difference is that in data everything is a symbol and nearly nothing is evaluated.

explicit symbols

As in other languages :symbols can be made explicit with a preceding colon. significant-whitespace differentiates this syntax from map notation a:b !

The colon symbol syntax is useful to uncharge operators without separating them via comma: a :plus b == a, plus, b

There is an interesting intermediary in uncharged code, where symbols can be dangling:

difference between assignment and declaration ( = / := )

assignment

All words on the left hand side of assignments are treated as symbols: x y z = y*y+u

x is a function declaration symbol
y is a bound argument symbol
z is an unused argument symbol (compiler error or warning)
u is an external symbol, evaluated immediately on construction, or deferred in the shell

⚠️ on assignment the compiler immediately emits an error if a symbol was not defined before

explicit declaration

x y z := y*y+u

u is an unbound external symbol, evaluated on calling x(y=1)
ok if u is available only on invocation, as parameter x(y=1,u=2)
ok if u is available only on invocation, in the context u=2; x(y=1)
=> error if u is still undefined or y*y+u!

⚠️ the above context consumption of u may be enforced with global keyword if using strict mode.

⚠️ on declaration the compiler emits an error if a symbol is not defined in invocations x();x!

What is the point of providing arguments, when unbound external symbols are resolved

x y z := y*y+u
x(y=2,u=3) # 7
y=2,u=3;x() # 7

arguments are more robust and allow pure functions. arguments are more more efficient, since unbound external symbols require function calls to query the current context on evaluation