Modular•13mo ago

How to Implement Recursive data type

I want to Implement abstract syntax tree in mojo, so far no luck, Something simple as this in C : https://github.com/orangeduck/mpc/blob/master/mpc.h#L291

struct ast {
  char *tag;
  char *contents;
  int children_num;
  struct ast** children;
}

struct ast {
  char *tag;
  char *contents;
  int children_num;
  struct ast** children;
}

GitHub

mpc/mpc.h at master · orangeduck/mpc

A Parser Combinator library for C. Contribute to orangeduck/mpc development by creating an account on GitHub.

2 Replies

Geo7OP•13mo ago

@value
@register_passable("trivial")
struct UnsafeString:
    var data: Pointer[Int8]
    var len: Int

    fn __init__(str: StringLiteral) -> UnsafeString:
        let l = str.__len__()
        let s = String(str)
        let p = Pointer[Int8].alloc(l)
        for i in range(l):
            p.store(i, s._buffer[i])
        return UnsafeString(p, l)

    fn to_string(self) -> String:
        let s = String(self.data, self.len)
        return s


@value
@register_passable("trivial")
struct AST:
    var tag: UnsafeString
    var content: UnsafeString
    var child_no: Int
    var children: Pointer[AST]


fn main():
    print("AST Started")
    var child1 = AST("Ident", "book", 0, 0)

@value
@register_passable("trivial")
struct UnsafeString:
    var data: Pointer[Int8]
    var len: Int

    fn __init__(str: StringLiteral) -> UnsafeString:
        let l = str.__len__()
        let s = String(str)
        let p = Pointer[Int8].alloc(l)
        for i in range(l):
            p.store(i, s._buffer[i])
        return UnsafeString(p, l)

    fn to_string(self) -> String:
        let s = String(self.data, self.len)
        return s


@value
@register_passable("trivial")
struct AST:
    var tag: UnsafeString
    var content: UnsafeString
    var child_no: Int
    var children: Pointer[AST]


fn main():
    print("AST Started")
    var child1 = AST("Ident", "book", 0, 0)

How could I create child1 without any children? OK, I've done that now I could not implement add_child()

@value
@register_passable("trivial")
struct UnsafeString:
    var data: Pointer[Int8]
    var len: Int

    fn __init__(str: StringLiteral) -> UnsafeString:
        let l = str.__len__()
        let s = String(str)
        let p = Pointer[Int8].alloc(l)
        for i in range(l):
            p.store(i, s._buffer[i])
        return UnsafeString(p, l)

    fn to_string(self) -> String:
        let s = String(self.data, self.len)
        return s


struct AST:
    var tag: UnsafeString
    var content: UnsafeString
    var child_no: Int
    var children: Pointer[AST]

    fn __init__(
        inout self,
        tag: UnsafeString = "ILLEGAL",
        content: UnsafeString = "un",
        child_no: Int = 0,
    ):
        self.tag = tag
        self.content = content
        self.child_no = child_no
        self.children = Pointer[AST].alloc(child_no * 2)

    fn add_child(inout self, owned other: Self):
        self.children.store(0, other)


fn main():
    print("AST Started")
    var child1 = AST()
    var child2 = AST()
    var parent = AST()

@value
@register_passable("trivial")
struct UnsafeString:
    var data: Pointer[Int8]
    var len: Int

    fn __init__(str: StringLiteral) -> UnsafeString:
        let l = str.__len__()
        let s = String(str)
        let p = Pointer[Int8].alloc(l)
        for i in range(l):
            p.store(i, s._buffer[i])
        return UnsafeString(p, l)

    fn to_string(self) -> String:
        let s = String(self.data, self.len)
        return s


struct AST:
    var tag: UnsafeString
    var content: UnsafeString
    var child_no: Int
    var children: Pointer[AST]

    fn __init__(
        inout self,
        tag: UnsafeString = "ILLEGAL",
        content: UnsafeString = "un",
        child_no: Int = 0,
    ):
        self.tag = tag
        self.content = content
        self.child_no = child_no
        self.children = Pointer[AST].alloc(child_no * 2)

    fn add_child(inout self, owned other: Self):
        self.children.store(0, other)


fn main():
    print("AST Started")
    var child1 = AST()
    var child2 = AST()
    var parent = AST()

I'm getting this error:

candidate not viable: method argument #1 cannot bind generic !mlirtype to memory-only type 'AST'

candidate not viable: method argument #1 cannot bind generic !mlirtype to memory-only type 'AST'

I can not convert AST to value & register_passable, then I get an other error: no matching function in call to 'init': var child1 = AST() ~~~^~ candidate not viable: callee expects at least 1 argument, but 0 were specified

@value
@register_passable("trivial")
struct UnsafeString:
    var data: Pointer[Int8]
    var len: Int

    fn __init__(str: StringLiteral) -> UnsafeString:
        let l = str.__len__()
        let s = String(str)
        let p = Pointer[Int8].alloc(l)
        for i in range(l):
            p.store(i, s._buffer[i])
        return UnsafeString(p, l)

    fn to_string(self) -> String:
        let s = String(self.data, self.len)
        return s


@value
@register_passable("trivial")
struct AST:
    var tag: UnsafeString
    var content: UnsafeString
    var child_no: Int
    var children: Pointer[AST]

    fn __init__(
        inout self,
        tag: UnsafeString = "ILLEGAL",
        content: UnsafeString = "un",
        child_no: Int = 0,
    ) -> AST:
        self.tag = tag
        self.content = content
        self.child_no = child_no
        self.children = Pointer[AST].alloc(child_no * 2)
        return self

    fn add_child(inout self, owned other: Self):
        self.children.store(0, other)


fn main():
    print("AST Started")
    var child1 = AST()
    var child2 = AST()
    var parent = AST()

@value
@register_passable("trivial")
struct UnsafeString:
    var data: Pointer[Int8]
    var len: Int

    fn __init__(str: StringLiteral) -> UnsafeString:
        let l = str.__len__()
        let s = String(str)
        let p = Pointer[Int8].alloc(l)
        for i in range(l):
            p.store(i, s._buffer[i])
        return UnsafeString(p, l)

    fn to_string(self) -> String:
        let s = String(self.data, self.len)
        return s


@value
@register_passable("trivial")
struct AST:
    var tag: UnsafeString
    var content: UnsafeString
    var child_no: Int
    var children: Pointer[AST]

    fn __init__(
        inout self,
        tag: UnsafeString = "ILLEGAL",
        content: UnsafeString = "un",
        child_no: Int = 0,
    ) -> AST:
        self.tag = tag
        self.content = content
        self.child_no = child_no
        self.children = Pointer[AST].alloc(child_no * 2)
        return self

    fn add_child(inout self, owned other: Self):
        self.children.store(0, other)


fn main():
    print("AST Started")
    var child1 = AST()
    var child2 = AST()
    var parent = AST()

is there a way to use memory.unsafe.bitcast to solve this ?

Geo7OP•13mo ago

Again I changed it and now getting new error, I can not post it here (I reached the limit) I posted it on github discussion https://github.com/modularml/mojo/discussions/1194

GitHub

How to Implement Recursive data type? · modularml mojo · Discussion...

NOTICE: I've read this post #69 anyway I want to Implement this with current unsafe features I want to Implement abstract syntax tree in mojo, so far no luck, Something simple as this in C : ht...

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Programming

How to Implement Recursive data type