Convert parsing while, if, fn exprs to use { }

This commit is contained in:
greg 2017-01-09 20:33:08 -08:00
parent 2b4d3e8516
commit 1fa56800c5
5 changed files with 60 additions and 43 deletions

View File

@ -1,11 +1,11 @@
fn outer()
fn inner(a)
fn outer() {
fn inner(a) {
a + 10
end
}
inner(20) + 8.3
end
}
outer()

View File

@ -1,17 +1,17 @@
fn add(a, b)
fn add(a, b) {
a + b
end
}
fn subtract(a, b)
fn subtract(a, b) {
a - b
end
}
fn main()
fn main() {
first_value = add(20, 20)
second_value = subtract(700, 650)
first_value + second_value
end
}
main()

View File

@ -1,24 +1,24 @@
fn hella(x)
fn hella(x) {
print("hey")
if x == 3 then
if x == 3 {
Null
else
} else {
hella(x + 1)
end
end
}
}
hella(0)
fn fib(x)
if x < 3 then
1
else
fib(x - 1) + fib(x - 2)
end
end
fn fib(x) {
if x < 3 {
1
} else {
fib(x - 1) + fib(x - 2)
}
}
fib(10)

View File

@ -9,17 +9,19 @@ use std::convert::From;
// program := (statement delimiter ?)*
// delimiter := Newline | Semicolon
// statement := declaration | expression
// declaration := Fn prototype (statement)* End
// declaration := Fn prototype LCurlyBrace (statement)* RCurlyBrace
// prototype := identifier LParen identlist RParen
// identlist := Ident (Comma Ident)* | e
// exprlist := Expression (Comma Expression)* | e
//
// expression := primary_expression (op primary_expression)*
// primary_expression := Number | String | identifier_expr | paren_expr | conditional_expr
// primary_expression := Number | String | identifier_expr | paren_expr | conditional_expr |
// while_expr
// identifier_expr := call_expression | Variable
// while_expr := WHILE primary_expression LCurlyBrace (expression delimiter)* RCurlyBrace
// paren_expr := LParen expression RParen
// call_expr := Identifier LParen exprlist RParen
// conditional_expr := IF expression THEN (expression delimiter?)* ELSE (expresion delimiter?)* END
// conditional_expr := IF expression LCurlyBrace (expression delimiter)* RCurlyBrace (LCurlyBrace (expresion delimiter)* RCurlyBrace)?
// op := '+', '-', etc.
//
@ -271,8 +273,9 @@ impl Parser {
fn declaration(&mut self) -> ParseResult<Statement> {
expect!(self, Keyword(Kw::Fn));
let prototype = try!(self.prototype());
expect!(self, LCurlyBrace);
let body = try!(self.body());
expect!(self, Keyword(Kw::End));
expect!(self, RCurlyBrace);
Ok(Statement::FuncDefNode(Function {
prototype: prototype,
body: body,
@ -323,7 +326,7 @@ impl Parser {
let statements = delimiter_block!(
self,
statement,
Some(Keyword(Kw::End))
Some(RCurlyBrace)
);
Ok(statements)
}
@ -390,12 +393,13 @@ impl Parser {
use self::Expression::*;
expect!(self, Keyword(Kw::While));
let test = try!(self.expression());
expect!(self, LCurlyBrace);
let body = delimiter_block!(
self,
expression,
Some(Keyword(Kw::End))
Some(RCurlyBrace)
);
expect!(self, Keyword(Kw::End));
expect!(self, RCurlyBrace);
Ok(While(Box::new(test), body))
}
@ -412,24 +416,35 @@ impl Parser {
_ => break,
}
}
expect!(self, Keyword(Kw::Then));
expect!(self, LCurlyBrace);
loop {
match self.peek() {
Some(ref t) if is_delimiter(t) => {
self.next();
continue;
}
_ => break,
}
}
let then_block = delimiter_block!(
self,
expression,
Some(Keyword(Kw::Else)) | Some(Keyword(Kw::End))
Some(RCurlyBrace)
);
expect!(self, RCurlyBrace);
let else_block = if let Some(Keyword(Kw::Else)) = self.peek() {
self.next();
expect!(self, LCurlyBrace);
let else_exprs = delimiter_block!(
self,
expression,
Some(Keyword(Kw::End))
Some(RCurlyBrace)
);
Some(else_exprs)
} else {
None
};
expect!(self, Keyword(Kw::End));
expect!(self, RCurlyBrace);
Ok(Conditional(Box::new(test),
Box::new(Block(VecDeque::from(then_block))),
else_block.map(|list| Box::new(Block(VecDeque::from(list))))))
@ -491,14 +506,14 @@ mod tests {
fn call_parse_test() {
use super::Function;
parsetest!(
"fn a() 1 + 2 end",
"fn a() { 1 + 2 }",
&[FuncDefNode(Function {prototype: Prototype { ref name, ref parameters }, ref body})],
match &body[..] { &[ExprNode(BinExp(_, box Number(1.0), box Number(2.0)))] => true, _ => false }
&& **name == "a" && match &parameters[..] { &[] => true, _ => false }
);
parsetest!(
"fn a(x,y) 1 + 2 end",
"fn a(x,y){ 1 + 2 }",
&[FuncDefNode(Function {prototype: Prototype { ref name, ref parameters }, ref body})],
match &body[..] { &[ExprNode(BinExp(_, box Number(1.0), box Number(2.0)))] => true, _ => false }
&& **name == "a" && *parameters[0] == "x" && *parameters[1] == "y" && parameters.len() == 2
@ -525,18 +540,20 @@ mod tests {
#[test]
fn conditional_parse_test() {
use tokenizer;
let t1 = "if null then 20 else 40 end";
let t1 = "if null { 20 } else { 40 }";
let tokens = tokenizer::tokenize(t1).unwrap();
match parse(&tokens, &[]).unwrap()[..] {
[ExprNode(Conditional(box Null, box Block(_), Some(box Block(_))))] => (),
_ => panic!(),
}
let t2 = "if null\nthen\n20\nelse\n40\nend";
/*
let t2 = "if null\n{\n20\n}\nelse {\n40\n}";
let tokens2 = tokenizer::tokenize(t2).unwrap();
match parse(&tokens2, &[]).unwrap()[..] {
[ExprNode(Conditional(box Null, box Block(_), Some(box Block(_))))] => (),
_ => panic!(),
}
*/
}
}

View File

@ -1,11 +1,11 @@
fn a(x)
x + 20
end
fn a(x) {
x + 20
}
fn x(x)
x + a(9384)
end
fn x(x) {
x + a(9384)
}
a(0)
x(1)