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</pre></div><pre class="rust"><code><span class="kw">use </span><span class="kw">crate</span>::lexer::{Lexer, Token};
<span class="attr">#[derive(Debug, PartialEq)]
</span><span class="kw">pub enum </span>ExprAST {
<span class="doccomment">/// Number - Expression class for numeric literals like "1.0".
</span>Number(f64),
<span class="doccomment">/// Variable - Expression class for referencing a variable, like "a".
</span>Variable(String),
<span class="doccomment">/// Binary - Expression class for a binary operator.
</span>Binary(char, Box<ExprAST>, Box<ExprAST>),
<span class="doccomment">/// Call - Expression class for function calls.
</span>Call(String, Vec<ExprAST>),
<span class="doccomment">/// If - Expression class for if/then/else.
</span>If {
cond: Box<ExprAST>,
then: Box<ExprAST>,
else_: Box<ExprAST>,
},
<span class="doccomment">/// ForExprAST - Expression class for for/in.
</span>For {
var: String,
start: Box<ExprAST>,
end: Box<ExprAST>,
step: <span class="prelude-ty">Option</span><Box<ExprAST>>,
body: Box<ExprAST>,
},
}
<span class="doccomment">/// PrototypeAST - This class represents the "prototype" for a function,
/// which captures its name, and its argument names (thus implicitly the number
/// of arguments the function takes).
</span><span class="attr">#[derive(Debug, PartialEq, Clone)]
</span><span class="kw">pub struct </span>PrototypeAST(<span class="kw">pub </span>String, <span class="kw">pub </span>Vec<String>);
<span class="doccomment">/// FunctionAST - This class represents a function definition itself.
</span><span class="attr">#[derive(Debug, PartialEq)]
</span><span class="kw">pub struct </span>FunctionAST(<span class="kw">pub </span>PrototypeAST, <span class="kw">pub </span>ExprAST);
<span class="doccomment">/// Parse result with String as Error type (to be compliant with tutorial).
</span><span class="kw">type </span>ParseResult<T> = <span class="prelude-ty">Result</span><T, String>;
<span class="doccomment">/// Parser for the `kaleidoscope` language.
</span><span class="kw">pub struct </span>Parser<I>
<span class="kw">where
</span>I: Iterator<Item = char>,
{
lexer: Lexer<I>,
cur_tok: <span class="prelude-ty">Option</span><Token>,
}
<span class="kw">impl</span><I> Parser<I>
<span class="kw">where
</span>I: Iterator<Item = char>,
{
<span class="kw">pub fn </span>new(lexer: Lexer<I>) -> <span class="self">Self </span>{
Parser {
lexer,
cur_tok: <span class="prelude-val">None</span>,
}
}
<span class="comment">// -----------------------
// Simple Token Buffer
// -----------------------
</span><span class="doccomment">/// Implement the global variable `int CurTok;` from the tutorial.
///
/// # Panics
/// Panics if the parser doesn't have a current token.
</span><span class="kw">pub fn </span>cur_tok(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="kw-2">&</span>Token {
<span class="self">self</span>.cur_tok.as_ref().expect(<span class="string">"Parser: Expected cur_token!"</span>)
}
<span class="doccomment">/// Advance the `cur_tok` by getting the next token from the lexer.
///
/// Implement the fucntion `int getNextToken();` from the tutorial.
</span><span class="kw">pub fn </span>get_next_token(<span class="kw-2">&mut </span><span class="self">self</span>) {
<span class="self">self</span>.cur_tok = <span class="prelude-val">Some</span>(<span class="self">self</span>.lexer.gettok());
}
<span class="comment">// ----------------------------
// Basic Expression Parsing
// ----------------------------
</span><span class="doccomment">/// numberexpr ::= number
///
/// Implement `std::unique_ptr<ExprAST> ParseNumberExpr();` from the tutorial.
</span><span class="kw">fn </span>parse_num_expr(<span class="kw-2">&mut </span><span class="self">self</span>) -> ParseResult<ExprAST> {
<span class="kw">match </span><span class="kw-2">*</span><span class="self">self</span>.cur_tok() {
Token::Number(num) => {
<span class="comment">// Consume the number token.
</span><span class="self">self</span>.get_next_token();
<span class="prelude-val">Ok</span>(ExprAST::Number(num))
}
<span class="kw">_ </span>=> <span class="macro">unreachable!</span>(),
}
}
<span class="doccomment">/// parenexpr ::= '(' expression ')'
///
/// Implement `std::unique_ptr<ExprAST> ParseParenExpr();` from the tutorial.
</span><span class="kw">fn </span>parse_paren_expr(<span class="kw-2">&mut </span><span class="self">self</span>) -> ParseResult<ExprAST> {
<span class="comment">// Eat '(' token.
</span><span class="macro">assert_eq!</span>(<span class="kw-2">*</span><span class="self">self</span>.cur_tok(), Token::Char(<span class="string">'('</span>));
<span class="self">self</span>.get_next_token();
<span class="kw">let </span>v = <span class="self">self</span>.parse_expression()<span class="question-mark">?</span>;
<span class="kw">if </span><span class="kw-2">*</span><span class="self">self</span>.cur_tok() == Token::Char(<span class="string">')'</span>) {
<span class="comment">// Eat ')' token.
</span><span class="self">self</span>.get_next_token();
<span class="prelude-val">Ok</span>(v)
} <span class="kw">else </span>{
<span class="prelude-val">Err</span>(<span class="string">"expected ')'"</span>.into())
}
}
<span class="doccomment">/// identifierexpr
/// ::= identifier
/// ::= identifier '(' expression* ')'
///
/// Implement `std::unique_ptr<ExprAST> ParseIdentifierExpr();` from the tutorial.
</span><span class="kw">fn </span>parse_identifier_expr(<span class="kw-2">&mut </span><span class="self">self</span>) -> ParseResult<ExprAST> {
<span class="kw">let </span>id_name = <span class="kw">match </span><span class="self">self</span>.cur_tok.take() {
<span class="prelude-val">Some</span>(Token::Identifier(id)) => {
<span class="comment">// Consume identifier.
</span><span class="self">self</span>.get_next_token();
id
}
<span class="kw">_ </span>=> <span class="macro">unreachable!</span>(),
};
<span class="kw">if </span><span class="kw-2">*</span><span class="self">self</span>.cur_tok() != Token::Char(<span class="string">'('</span>) {
<span class="comment">// Simple variable reference.
</span><span class="prelude-val">Ok</span>(ExprAST::Variable(id_name))
} <span class="kw">else </span>{
<span class="comment">// Call.
// Eat '(' token.
</span><span class="self">self</span>.get_next_token();
<span class="kw">let </span><span class="kw-2">mut </span>args: Vec<ExprAST> = Vec::new();
<span class="comment">// If there are arguments collect them.
</span><span class="kw">if </span><span class="kw-2">*</span><span class="self">self</span>.cur_tok() != Token::Char(<span class="string">')'</span>) {
<span class="kw">loop </span>{
<span class="kw">let </span>arg = <span class="self">self</span>.parse_expression()<span class="question-mark">?</span>;
args.push(arg);
<span class="kw">if </span><span class="kw-2">*</span><span class="self">self</span>.cur_tok() == Token::Char(<span class="string">')'</span>) {
<span class="kw">break</span>;
}
<span class="kw">if </span><span class="kw-2">*</span><span class="self">self</span>.cur_tok() != Token::Char(<span class="string">','</span>) {
<span class="kw">return </span><span class="prelude-val">Err</span>(<span class="string">"Expected ')' or ',' in argument list"</span>.into());
}
<span class="self">self</span>.get_next_token();
}
}
<span class="macro">assert_eq!</span>(<span class="kw-2">*</span><span class="self">self</span>.cur_tok(), Token::Char(<span class="string">')'</span>));
<span class="comment">// Eat ')' token.
</span><span class="self">self</span>.get_next_token();
<span class="prelude-val">Ok</span>(ExprAST::Call(id_name, args))
}
}
<span class="doccomment">/// ifexpr ::= 'if' expression 'then' expression 'else' expression
///
/// Implement `std::unique_ptr<ExprAST> ParseIfExpr();` from the tutorial.
</span><span class="kw">fn </span>parse_if_expr(<span class="kw-2">&mut </span><span class="self">self</span>) -> ParseResult<ExprAST> {
<span class="comment">// Consume 'if' token.
</span><span class="macro">assert_eq!</span>(<span class="kw-2">*</span><span class="self">self</span>.cur_tok(), Token::If);
<span class="self">self</span>.get_next_token();
<span class="kw">let </span>cond = <span class="self">self</span>.parse_expression()<span class="question-mark">?</span>;
<span class="kw">if </span><span class="kw-2">*</span><span class="macro">dbg!</span>(<span class="self">self</span>.cur_tok()) != Token::Then {
<span class="kw">return </span><span class="prelude-val">Err</span>(<span class="string">"Expected 'then'"</span>.into());
}
<span class="comment">// Consume 'then' token.
</span><span class="self">self</span>.get_next_token();
<span class="kw">let </span>then = <span class="self">self</span>.parse_expression()<span class="question-mark">?</span>;
<span class="kw">if </span><span class="kw-2">*</span><span class="self">self</span>.cur_tok() != Token::Else {
<span class="kw">return </span><span class="prelude-val">Err</span>(<span class="string">"Expected 'else'"</span>.into());
}
<span class="comment">// Consume 'else' token.
</span><span class="self">self</span>.get_next_token();
<span class="kw">let </span>else_ = <span class="self">self</span>.parse_expression()<span class="question-mark">?</span>;
<span class="prelude-val">Ok</span>(ExprAST::If {
cond: Box::new(cond),
then: Box::new(then),
else_: Box::new(else_),
})
}
<span class="doccomment">/// forexpr ::= 'for' identifier '=' expr ',' expr (',' expr)? 'in' expression
///
/// Implement `std::unique_ptr<ExprAST> ParseForExpr();` from the tutorial.
</span><span class="kw">fn </span>parse_for_expr(<span class="kw-2">&mut </span><span class="self">self</span>) -> ParseResult<ExprAST> {
<span class="comment">// Consume the 'for' token.
</span><span class="macro">assert_eq!</span>(<span class="kw-2">*</span><span class="self">self</span>.cur_tok(), Token::For);
<span class="self">self</span>.get_next_token();
<span class="kw">let </span>var = <span class="kw">match </span><span class="self">self
</span>.parse_identifier_expr()
.map_err(|<span class="kw">_</span>| String::from(<span class="string">"expected identifier after 'for'"</span>))<span class="question-mark">?
</span>{
ExprAST::Variable(var) => var,
<span class="kw">_ </span>=> <span class="macro">unreachable!</span>(),
};
<span class="comment">// Consume the '=' token.
</span><span class="kw">if </span><span class="kw-2">*</span><span class="self">self</span>.cur_tok() != Token::Char(<span class="string">'='</span>) {
<span class="kw">return </span><span class="prelude-val">Err</span>(<span class="string">"expected '=' after for"</span>.into());
}
<span class="self">self</span>.get_next_token();
<span class="kw">let </span>start = <span class="self">self</span>.parse_expression()<span class="question-mark">?</span>;
<span class="comment">// Consume the ',' token.
</span><span class="kw">if </span><span class="kw-2">*</span><span class="self">self</span>.cur_tok() != Token::Char(<span class="string">','</span>) {
<span class="kw">return </span><span class="prelude-val">Err</span>(<span class="string">"expected ',' after for start value"</span>.into());
}
<span class="self">self</span>.get_next_token();
<span class="kw">let </span>end = <span class="self">self</span>.parse_expression()<span class="question-mark">?</span>;
<span class="kw">let </span>step = <span class="kw">if </span><span class="kw-2">*</span><span class="self">self</span>.cur_tok() == Token::Char(<span class="string">','</span>) {
<span class="comment">// Consume the ',' token.
</span><span class="self">self</span>.get_next_token();
<span class="prelude-val">Some</span>(<span class="self">self</span>.parse_expression()<span class="question-mark">?</span>)
} <span class="kw">else </span>{
<span class="prelude-val">None
</span>};
<span class="comment">// Consume the 'in' token.
</span><span class="kw">if </span><span class="kw-2">*</span><span class="self">self</span>.cur_tok() != Token::In {
<span class="kw">return </span><span class="prelude-val">Err</span>(<span class="string">"expected 'in' after for"</span>.into());
}
<span class="self">self</span>.get_next_token();
<span class="kw">let </span>body = <span class="self">self</span>.parse_expression()<span class="question-mark">?</span>;
<span class="prelude-val">Ok</span>(ExprAST::For {
var,
start: Box::new(start),
end: Box::new(end),
step: step.map(|s| Box::new(s)),
body: Box::new(body),
})
}
<span class="doccomment">/// primary
/// ::= identifierexpr
/// ::= numberexpr
/// ::= parenexpr
///
/// Implement `std::unique_ptr<ExprAST> ParsePrimary();` from the tutorial.
</span><span class="kw">fn </span>parse_primary(<span class="kw-2">&mut </span><span class="self">self</span>) -> ParseResult<ExprAST> {
<span class="kw">match </span><span class="kw-2">*</span><span class="self">self</span>.cur_tok() {
Token::Identifier(<span class="kw">_</span>) => <span class="self">self</span>.parse_identifier_expr(),
Token::Number(<span class="kw">_</span>) => <span class="self">self</span>.parse_num_expr(),
Token::Char(<span class="string">'('</span>) => <span class="self">self</span>.parse_paren_expr(),
Token::If => <span class="self">self</span>.parse_if_expr(),
Token::For => <span class="self">self</span>.parse_for_expr(),
<span class="kw">_ </span>=> <span class="prelude-val">Err</span>(<span class="string">"unknown token when expecting an expression"</span>.into()),
}
}
<span class="comment">// -----------------------------
// Binary Expression Parsing
// -----------------------------
</span><span class="doccomment">/// /// expression
/// ::= primary binoprhs
///
/// Implement `std::unique_ptr<ExprAST> ParseExpression();` from the tutorial.
</span><span class="kw">fn </span>parse_expression(<span class="kw-2">&mut </span><span class="self">self</span>) -> ParseResult<ExprAST> {
<span class="kw">let </span>lhs = <span class="self">self</span>.parse_primary()<span class="question-mark">?</span>;
<span class="self">self</span>.parse_bin_op_rhs(<span class="number">0</span>, lhs)
}
<span class="doccomment">/// binoprhs
/// ::= ('+' primary)*
///
/// Implement `std::unique_ptr<ExprAST> ParseBinOpRHS(int ExprPrec, std::unique_ptr<ExprAST> LHS);` from the tutorial.
</span><span class="kw">fn </span>parse_bin_op_rhs(<span class="kw-2">&mut </span><span class="self">self</span>, expr_prec: isize, <span class="kw-2">mut </span>lhs: ExprAST) -> ParseResult<ExprAST> {
<span class="kw">loop </span>{
<span class="kw">let </span>tok_prec = get_tok_precedence(<span class="self">self</span>.cur_tok());
<span class="comment">// Not a binary operator or precedence is too small.
</span><span class="kw">if </span>tok_prec < expr_prec {
<span class="kw">return </span><span class="prelude-val">Ok</span>(lhs);
}
<span class="kw">let </span>binop = <span class="kw">match </span><span class="self">self</span>.cur_tok.take() {
<span class="prelude-val">Some</span>(Token::Char(c)) => {
<span class="comment">// Eat binary operator.
</span><span class="self">self</span>.get_next_token();
c
}
<span class="kw">_ </span>=> <span class="macro">unreachable!</span>(),
};
<span class="comment">// lhs BINOP1 rhs BINOP2 remrhs
// ^^^^^^ ^^^^^^
// tok_prec next_prec
//
// In case BINOP1 has higher precedence, we are done here and can build a 'Binary' AST
// node between 'lhs' and 'rhs'.
//
// In case BINOP2 has higher precedence, we take 'rhs' as 'lhs' and recurse into the
// 'remrhs' expression first.
// Parse primary expression after binary operator.
</span><span class="kw">let </span><span class="kw-2">mut </span>rhs = <span class="self">self</span>.parse_primary()<span class="question-mark">?</span>;
<span class="kw">let </span>next_prec = get_tok_precedence(<span class="self">self</span>.cur_tok());
<span class="kw">if </span>tok_prec < next_prec {
<span class="comment">// BINOP2 has higher precedence thatn BINOP1, recurse into 'remhs'.
</span>rhs = <span class="self">self</span>.parse_bin_op_rhs(tok_prec + <span class="number">1</span>, rhs)<span class="question-mark">?
</span>}
lhs = ExprAST::Binary(binop, Box::new(lhs), Box::new(rhs));
}
}
<span class="comment">// --------------------
// Parsing the Rest
// --------------------
</span><span class="doccomment">/// prototype
/// ::= id '(' id* ')'
///
/// Implement `std::unique_ptr<PrototypeAST> ParsePrototype();` from the tutorial.
</span><span class="kw">fn </span>parse_prototype(<span class="kw-2">&mut </span><span class="self">self</span>) -> ParseResult<PrototypeAST> {
<span class="kw">let </span>id_name = <span class="kw">match </span><span class="self">self</span>.cur_tok.take() {
<span class="prelude-val">Some</span>(Token::Identifier(id)) => {
<span class="comment">// Consume the identifier.
</span><span class="self">self</span>.get_next_token();
id
}
other => {
<span class="comment">// Plug back current token.
</span><span class="self">self</span>.cur_tok = other;
<span class="kw">return </span><span class="prelude-val">Err</span>(<span class="string">"Expected function name in prototype"</span>.into());
}
};
<span class="kw">if </span><span class="kw-2">*</span><span class="self">self</span>.cur_tok() != Token::Char(<span class="string">'('</span>) {
<span class="kw">return </span><span class="prelude-val">Err</span>(<span class="string">"Expected '(' in prototype"</span>.into());
}
<span class="kw">let </span><span class="kw-2">mut </span>args: Vec<String> = Vec::new();
<span class="kw">loop </span>{
<span class="self">self</span>.get_next_token();
<span class="kw">match </span><span class="self">self</span>.cur_tok.take() {
<span class="prelude-val">Some</span>(Token::Identifier(arg)) => args.push(arg),
<span class="prelude-val">Some</span>(Token::Char(<span class="string">','</span>)) => {}
other => {
<span class="self">self</span>.cur_tok = other;
<span class="kw">break</span>;
}
}
}
<span class="kw">if </span><span class="kw-2">*</span><span class="self">self</span>.cur_tok() != Token::Char(<span class="string">')'</span>) {
<span class="kw">return </span><span class="prelude-val">Err</span>(<span class="string">"Expected ')' in prototype"</span>.into());
}
<span class="comment">// Consume ')'.
</span><span class="self">self</span>.get_next_token();
<span class="prelude-val">Ok</span>(PrototypeAST(id_name, args))
}
<span class="doccomment">/// definition ::= 'def' prototype expression
///
/// Implement `std::unique_ptr<FunctionAST> ParseDefinition();` from the tutorial.
</span><span class="kw">pub fn </span>parse_definition(<span class="kw-2">&mut </span><span class="self">self</span>) -> ParseResult<FunctionAST> {
<span class="comment">// Consume 'def' token.
</span><span class="macro">assert_eq!</span>(<span class="kw-2">*</span><span class="self">self</span>.cur_tok(), Token::Def);
<span class="self">self</span>.get_next_token();
<span class="kw">let </span>proto = <span class="self">self</span>.parse_prototype()<span class="question-mark">?</span>;
<span class="kw">let </span>expr = <span class="self">self</span>.parse_expression()<span class="question-mark">?</span>;
<span class="prelude-val">Ok</span>(FunctionAST(proto, expr))
}
<span class="doccomment">/// external ::= 'extern' prototype
///
/// Implement `std::unique_ptr<PrototypeAST> ParseExtern();` from the tutorial.
</span><span class="kw">pub fn </span>parse_extern(<span class="kw-2">&mut </span><span class="self">self</span>) -> ParseResult<PrototypeAST> {
<span class="comment">// Consume 'extern' token.
</span><span class="macro">assert_eq!</span>(<span class="kw-2">*</span><span class="self">self</span>.cur_tok(), Token::Extern);
<span class="self">self</span>.get_next_token();
<span class="self">self</span>.parse_prototype()
}
<span class="doccomment">/// toplevelexpr ::= expression
///
/// Implement `std::unique_ptr<FunctionAST> ParseTopLevelExpr();` from the tutorial.
</span><span class="kw">pub fn </span>parse_top_level_expr(<span class="kw-2">&mut </span><span class="self">self</span>) -> ParseResult<FunctionAST> {
<span class="kw">let </span>e = <span class="self">self</span>.parse_expression()<span class="question-mark">?</span>;
<span class="kw">let </span>proto = PrototypeAST(<span class="string">"__anon_expr"</span>.into(), Vec::new());
<span class="prelude-val">Ok</span>(FunctionAST(proto, e))
}
}
<span class="doccomment">/// Get the binary operator precedence.
///
/// Implement `int GetTokPrecedence();` from the tutorial.
</span><span class="kw">fn </span>get_tok_precedence(tok: <span class="kw-2">&</span>Token) -> isize {
<span class="kw">match </span>tok {
Token::Char(<span class="string">'<'</span>) => <span class="number">10</span>,
Token::Char(<span class="string">'+'</span>) => <span class="number">20</span>,
Token::Char(<span class="string">'-'</span>) => <span class="number">20</span>,
Token::Char(<span class="string">'*'</span>) => <span class="number">40</span>,
<span class="kw">_ </span>=> -<span class="number">1</span>,
}
}
<span class="attr">#[cfg(test)]
</span><span class="kw">mod </span>test {
<span class="kw">use super</span>::{ExprAST, FunctionAST, Parser, PrototypeAST};
<span class="kw">use </span><span class="kw">crate</span>::lexer::Lexer;
<span class="kw">fn </span>parser(input: <span class="kw-2">&</span>str) -> Parser<std::str::Chars> {
<span class="kw">let </span>l = Lexer::new(input.chars());
<span class="kw">let </span><span class="kw-2">mut </span>p = Parser::new(l);
<span class="comment">// Drop initial coin, initialize cur_tok.
</span>p.get_next_token();
p
}
<span class="attr">#[test]
</span><span class="kw">fn </span>parse_number() {
<span class="kw">let </span><span class="kw-2">mut </span>p = parser(<span class="string">"13.37"</span>);
<span class="macro">assert_eq!</span>(p.parse_num_expr(), <span class="prelude-val">Ok</span>(ExprAST::Number(<span class="number">13.37f64</span>)));
}
<span class="attr">#[test]
</span><span class="kw">fn </span>parse_variable() {
<span class="kw">let </span><span class="kw-2">mut </span>p = parser(<span class="string">"foop"</span>);
<span class="macro">assert_eq!</span>(
p.parse_identifier_expr(),
<span class="prelude-val">Ok</span>(ExprAST::Variable(<span class="string">"foop"</span>.into()))
);
}
<span class="attr">#[test]
</span><span class="kw">fn </span>parse_if() {
<span class="kw">let </span><span class="kw-2">mut </span>p = parser(<span class="string">"if 1 then 2 else 3"</span>);
<span class="kw">let </span>cond = Box::new(ExprAST::Number(<span class="number">1f64</span>));
<span class="kw">let </span>then = Box::new(ExprAST::Number(<span class="number">2f64</span>));
<span class="kw">let </span>else_ = Box::new(ExprAST::Number(<span class="number">3f64</span>));
<span class="macro">assert_eq!</span>(p.parse_if_expr(), <span class="prelude-val">Ok</span>(ExprAST::If { cond, then, else_ }));
<span class="kw">let </span><span class="kw-2">mut </span>p = parser(<span class="string">"if foo() then bar(2) else baz(3)"</span>);
<span class="kw">let </span>cond = Box::new(ExprAST::Call(<span class="string">"foo"</span>.into(), <span class="macro">vec!</span>[]));
<span class="kw">let </span>then = Box::new(ExprAST::Call(<span class="string">"bar"</span>.into(), <span class="macro">vec!</span>[ExprAST::Number(<span class="number">2f64</span>)]));
<span class="kw">let </span>else_ = Box::new(ExprAST::Call(<span class="string">"baz"</span>.into(), <span class="macro">vec!</span>[ExprAST::Number(<span class="number">3f64</span>)]));
<span class="macro">assert_eq!</span>(p.parse_if_expr(), <span class="prelude-val">Ok</span>(ExprAST::If { cond, then, else_ }));
}
<span class="attr">#[test]
</span><span class="kw">fn </span>parse_for() {
<span class="kw">let </span><span class="kw-2">mut </span>p = parser(<span class="string">"for i = 1, 2, 3 in 4"</span>);
<span class="kw">let </span>var = String::from(<span class="string">"i"</span>);
<span class="kw">let </span>start = Box::new(ExprAST::Number(<span class="number">1f64</span>));
<span class="kw">let </span>end = Box::new(ExprAST::Number(<span class="number">2f64</span>));
<span class="kw">let </span>step = <span class="prelude-val">Some</span>(Box::new(ExprAST::Number(<span class="number">3f64</span>)));
<span class="kw">let </span>body = Box::new(ExprAST::Number(<span class="number">4f64</span>));
<span class="macro">assert_eq!</span>(
p.parse_for_expr(),
<span class="prelude-val">Ok</span>(ExprAST::For {
var,
start,
end,
step,
body
})
);
}
<span class="attr">#[test]
</span><span class="kw">fn </span>parse_for_no_step() {
<span class="kw">let </span><span class="kw-2">mut </span>p = parser(<span class="string">"for i = 1, 2 in 4"</span>);
<span class="kw">let </span>var = String::from(<span class="string">"i"</span>);
<span class="kw">let </span>start = Box::new(ExprAST::Number(<span class="number">1f64</span>));
<span class="kw">let </span>end = Box::new(ExprAST::Number(<span class="number">2f64</span>));
<span class="kw">let </span>step = <span class="prelude-val">None</span>;
<span class="kw">let </span>body = Box::new(ExprAST::Number(<span class="number">4f64</span>));
<span class="macro">assert_eq!</span>(
p.parse_for_expr(),
<span class="prelude-val">Ok</span>(ExprAST::For {
var,
start,
end,
step,
body
})
);
}
<span class="attr">#[test]
</span><span class="kw">fn </span>parse_primary() {
<span class="kw">let </span><span class="kw-2">mut </span>p = parser(<span class="string">"1337 foop \n bla(123) \n if a then b else c \n for x=1,2 in 3"</span>);
<span class="macro">assert_eq!</span>(p.parse_primary(), <span class="prelude-val">Ok</span>(ExprAST::Number(<span class="number">1337f64</span>)));
<span class="macro">assert_eq!</span>(p.parse_primary(), <span class="prelude-val">Ok</span>(ExprAST::Variable(<span class="string">"foop"</span>.into())));
<span class="macro">assert_eq!</span>(
p.parse_primary(),
<span class="prelude-val">Ok</span>(ExprAST::Call(<span class="string">"bla"</span>.into(), <span class="macro">vec!</span>[ExprAST::Number(<span class="number">123f64</span>)]))
);
<span class="macro">assert_eq!</span>(
p.parse_primary(),
<span class="prelude-val">Ok</span>(ExprAST::If {
cond: Box::new(ExprAST::Variable(<span class="string">"a"</span>.into())),
then: Box::new(ExprAST::Variable(<span class="string">"b"</span>.into())),
else_: Box::new(ExprAST::Variable(<span class="string">"c"</span>.into())),
})
);
<span class="macro">assert_eq!</span>(
p.parse_primary(),
<span class="prelude-val">Ok</span>(ExprAST::For {
var: String::from(<span class="string">"x"</span>),
start: Box::new(ExprAST::Number(<span class="number">1f64</span>)),
end: Box::new(ExprAST::Number(<span class="number">2f64</span>)),
step: <span class="prelude-val">None</span>,
body: Box::new(ExprAST::Number(<span class="number">3f64</span>)),
})
);
}
<span class="attr">#[test]
</span><span class="kw">fn </span>parse_binary_op() {
<span class="comment">// Operator before RHS has higher precedence, expected AST
//
// -
// / \
// + c
// / \
// a b
</span><span class="kw">let </span><span class="kw-2">mut </span>p = parser(<span class="string">"a + b - c"</span>);
<span class="kw">let </span>binexpr_ab = ExprAST::Binary(
<span class="string">'+'</span>,
Box::new(ExprAST::Variable(<span class="string">"a"</span>.into())),
Box::new(ExprAST::Variable(<span class="string">"b"</span>.into())),
);
<span class="kw">let </span>binexpr_abc = ExprAST::Binary(
<span class="string">'-'</span>,
Box::new(binexpr_ab),
Box::new(ExprAST::Variable(<span class="string">"c"</span>.into())),
);
<span class="macro">assert_eq!</span>(p.parse_expression(), <span class="prelude-val">Ok</span>(binexpr_abc));
}
<span class="attr">#[test]
</span><span class="kw">fn </span>parse_binary_op2() {
<span class="comment">// Operator after RHS has higher precedence, expected AST
//
// +
// / \
// a *
// / \
// b c
</span><span class="kw">let </span><span class="kw-2">mut </span>p = parser(<span class="string">"a + b * c"</span>);
<span class="kw">let </span>binexpr_bc = ExprAST::Binary(
<span class="string">'*'</span>,
Box::new(ExprAST::Variable(<span class="string">"b"</span>.into())),
Box::new(ExprAST::Variable(<span class="string">"c"</span>.into())),
);
<span class="kw">let </span>binexpr_abc = ExprAST::Binary(
<span class="string">'+'</span>,
Box::new(ExprAST::Variable(<span class="string">"a"</span>.into())),
Box::new(binexpr_bc),
);
<span class="macro">assert_eq!</span>(p.parse_expression(), <span class="prelude-val">Ok</span>(binexpr_abc));
}
<span class="attr">#[test]
</span><span class="kw">fn </span>parse_prototype() {
<span class="kw">let </span><span class="kw-2">mut </span>p = parser(<span class="string">"foo(a,b)"</span>);
<span class="kw">let </span>proto = PrototypeAST(<span class="string">"foo"</span>.into(), <span class="macro">vec!</span>[<span class="string">"a"</span>.into(), <span class="string">"b"</span>.into()]);
<span class="macro">assert_eq!</span>(p.parse_prototype(), <span class="prelude-val">Ok</span>(proto));
}
<span class="attr">#[test]
</span><span class="kw">fn </span>parse_definition() {
<span class="kw">let </span><span class="kw-2">mut </span>p = parser(<span class="string">"def bar( arg0 , arg1 ) arg0 + arg1"</span>);
<span class="kw">let </span>proto = PrototypeAST(<span class="string">"bar"</span>.into(), <span class="macro">vec!</span>[<span class="string">"arg0"</span>.into(), <span class="string">"arg1"</span>.into()]);
<span class="kw">let </span>body = ExprAST::Binary(
<span class="string">'+'</span>,
Box::new(ExprAST::Variable(<span class="string">"arg0"</span>.into())),
Box::new(ExprAST::Variable(<span class="string">"arg1"</span>.into())),
);
<span class="kw">let </span>func = FunctionAST(proto, body);
<span class="macro">assert_eq!</span>(p.parse_definition(), <span class="prelude-val">Ok</span>(func));
}
<span class="attr">#[test]
</span><span class="kw">fn </span>parse_extern() {
<span class="kw">let </span><span class="kw-2">mut </span>p = parser(<span class="string">"extern baz()"</span>);
<span class="kw">let </span>proto = PrototypeAST(<span class="string">"baz"</span>.into(), <span class="macro">vec!</span>[]);
<span class="macro">assert_eq!</span>(p.parse_extern(), <span class="prelude-val">Ok</span>(proto));
}
}
</code></pre></div></section></main></body></html>