remove if-expressions

zokrates_book/src/language/control_flow.md

@@ -18,18 +18,12 @@ Generic paramaters, if any, must be compile-time constants. They are inferred by
 {{#include ../../../zokrates_cli/examples/book/generic_call.zok}}
 ```
 
-### If-expressions
+### Conditional expressions
 
-An if-expression allows you to branch your code depending on a boolean condition.
+A conditional expression allows you to branch your code depending on a boolean condition. This can be written using a ternary operator:
 
 ```zokrates
-{{#include ../../../zokrates_cli/examples/book/if_else.zok}}
+{{#include ../../../zokrates_cli/examples/book/conditional_ternary.zok}}
-```
-
-The conditional expression can also be written using a ternary operator:
-
-```zokrates
-{{#include ../../../zokrates_cli/examples/book/ternary.zok}}
 ```
 
 There are two important caveats when it comes to conditional expressions. Before we go into them, let's define two concepts:
@@ -39,11 +33,11 @@ There are two important caveats when it comes to conditional expressions. Before
 Now the two caveats:
 - **Both branches are always executed**. No short-circuiting happens based on the value of the condition. Therefore, the complexity of a program in terms of the number of constraints it compiles down to is the *sum* of the cost of all branches.
 ```zokrates
-{{#include ../../../zokrates_cli/examples/book/if_else_expensive.zok}}
+{{#include ../../../zokrates_cli/examples/book/conditional_expensive.zok}}
 ```
 - **An unsatisfied constraint inside any branch will make the whole execution fail, even if this branch is not logically executed**. Also, the compiler itself inserts assertions which can fail. This can lead to unexpected results:
 ```zokrates
-{{#include ../../../zokrates_cli/examples/book/if_else_panic.zok}}
+{{#include ../../../zokrates_cli/examples/book/conditional_panic.zok}}
 ```
 The experimental flag `--branch-isolation` can be activated in the CLI in order to restrict any unsatisfied constraint to make the execution fail only if it is in a logically executed branch. This way, the execution of the program above will always succeed.
 

zokrates_book/src/language/operators.md

@@ -17,7 +17,7 @@ The following table lists the precedence and associativity of all operators. Ope
 | `!=`<br>`==`<br>           | Not Equal<br>Equal<br>                                     | &check;                      | &check;                       | &check;                     | Left          |
 | `&&`                       | Boolean AND                                                | &nbsp;                       | &nbsp;                        | &check;                     | Left          |
 | <code>&#124;&#124;</code>  | Boolean OR                                                 | &nbsp;                       | &nbsp;                        | &check;                     | Left          |
-| `c ? x : y`<br><br>`if c then x else y fi`    | Conditional expression                                     | &check;                      | &check;                       | &check;                     | Right         |         |
+| `c ? x : y`                | Conditional expression                                     | &check;                      | &check;                       | &check;                     | Right         |         |
 
 [^1]: The exponent must be a compile-time constant of type `u32`
 

zokrates_cli/examples/book/conditional_expensive.zok

@@ -0,0 +1,11 @@
+def cheap(field x) -> field {
+    return x + 1;
+}
+
+def expensive(field x) -> field {
+    return x**1000;
+}
+
+def main(field x) -> field {
+    return x == 1 ? cheap(x) : expensive(x); // both branches executed
+}

zokrates_cli/examples/book/conditional_panic.zok

@@ -0,0 +1,3 @@
+def main(field x) -> field {
+    return x == 0 ? 0 : 1 / x; // executed even for x := 0, which leads to the execution failing
+}

zokrates_cli/examples/book/conditional_ternary.zok

@@ -0,0 +1,4 @@
+def main(field x) -> field {
+    field y = x + 2 == 3 ? 1 : 5;
+    return y;
+}

zokrates_cli/examples/book/if_else.zok

@@ -1,3 +0,0 @@
-def main(field x) -> field:
-  field y = if x + 2 == 3 then 1 else 5 fi
-  return y

zokrates_cli/examples/book/if_else_expensive.zok

@@ -1,12 +0,0 @@
-def cheap(field x) -> field:
-    return x + 1
-
-def expensive(field x) -> field:
-    return x**1000
-
-def main(field x) -> field:
-    return if x == 1 then\
-        cheap(x)\// executed
-        else\
-        expensive(x)\// also executed
-    fi

zokrates_cli/examples/book/if_else_panic.zok

@@ -1,6 +0,0 @@
-def main(field x) -> field:
-    return if x == 0 then\
-        0\
-        else\
-        1/x\// executed even for x := 0, which leads to the execution failing
-    fi

zokrates_cli/examples/book/ternary.zok

@@ -1,3 +0,0 @@
-def main(field x) -> field:
-  field y = x + 2 == 3 ? 1 : 5
-  return y

zokrates_core/src/absy/from_ast.rs

@@ -405,7 +405,6 @@ impl<'ast> From<pest::Expression<'ast>> for absy::ExpressionNode<'ast> {
         match expression {
             pest::Expression::Binary(e) => absy::ExpressionNode::from(e),
             pest::Expression::Ternary(e) => absy::ExpressionNode::from(e),
-            pest::Expression::IfElse(e) => absy::ExpressionNode::from(e),
             pest::Expression::Literal(e) => absy::ExpressionNode::from(e),
             pest::Expression::Identifier(e) => absy::ExpressionNode::from(e),
             pest::Expression::Postfix(e) => absy::ExpressionNode::from(e),
@@ -507,19 +506,6 @@ impl<'ast> From<pest::BinaryExpression<'ast>> for absy::ExpressionNode<'ast> {
     }
 }
 
-impl<'ast> From<pest::IfElseExpression<'ast>> for absy::ExpressionNode<'ast> {
-    fn from(expression: pest::IfElseExpression<'ast>) -> absy::ExpressionNode<'ast> {
-        use crate::absy::NodeValue;
-        absy::Expression::Conditional(
-            box absy::ExpressionNode::from(*expression.condition),
-            box absy::ExpressionNode::from(*expression.consequence),
-            box absy::ExpressionNode::from(*expression.alternative),
-            absy::ConditionalKind::IfElse,
-        )
-        .span(expression.span)
-    }
-}
-
 impl<'ast> From<pest::TernaryExpression<'ast>> for absy::ExpressionNode<'ast> {
     fn from(expression: pest::TernaryExpression<'ast>) -> absy::ExpressionNode<'ast> {
         use crate::absy::NodeValue;
@@ -527,7 +513,6 @@ impl<'ast> From<pest::TernaryExpression<'ast>> for absy::ExpressionNode<'ast> {
             box absy::ExpressionNode::from(*expression.condition),
             box absy::ExpressionNode::from(*expression.consequence),
             box absy::ExpressionNode::from(*expression.alternative),
-            absy::ConditionalKind::Ternary,
         )
         .span(expression.span)
     }

zokrates_core/src/absy/mod.rs

@@ -510,12 +510,6 @@ impl<'ast> fmt::Display for Range<'ast> {
     }
 }
 
-#[derive(Debug, Clone, PartialEq)]
-pub enum ConditionalKind {
-    IfElse,
-    Ternary,
-}
-
 /// An expression
 #[derive(Debug, Clone, PartialEq)]
 pub enum Expression<'ast> {
@@ -539,7 +533,6 @@ pub enum Expression<'ast> {
         Box<ExpressionNode<'ast>>,
         Box<ExpressionNode<'ast>>,
         Box<ExpressionNode<'ast>>,
-        ConditionalKind,
     ),
     FunctionCall(
         Box<ExpressionNode<'ast>>,
@@ -589,17 +582,8 @@ impl<'ast> fmt::Display for Expression<'ast> {
             Expression::Neg(ref e) => write!(f, "(-{})", e),
             Expression::Pos(ref e) => write!(f, "(+{})", e),
             Expression::BooleanConstant(b) => write!(f, "{}", b),
-            Expression::Conditional(ref condition, ref consequent, ref alternative, ref kind) => {
+            Expression::Conditional(ref condition, ref consequent, ref alternative) => {
-                match kind {
+                write!(f, "{} ? {} : {}", condition, consequent, alternative)
-                    ConditionalKind::IfElse => write!(
-                        f,
-                        "if {} then {} else {} fi",
-                        condition, consequent, alternative
-                    ),
-                    ConditionalKind::Ternary => {
-                        write!(f, "{} ? {} : {}", condition, consequent, alternative)
-                    }
-                }
             }
             Expression::FunctionCall(ref i, ref g, ref p) => {
                 if let Some(g) = g {

zokrates_core/src/semantics.rs

@@ -2461,7 +2461,7 @@ impl<'ast, T: Field> Checker<'ast, T> {
                     }),
                 }
             }
-            Expression::Conditional(box condition, box consequence, box alternative, kind) => {
+            Expression::Conditional(box condition, box consequence, box alternative) => {
                 let condition_checked = self.check_expression(condition, module_id, types)?;
                 let consequence_checked = self.check_expression(consequence, module_id, types)?;
                 let alternative_checked = self.check_expression(alternative, module_id, types)?;
@@ -2476,35 +2476,26 @@ impl<'ast, T: Field> Checker<'ast, T> {
                         message: format!("{{consequence}} and {{alternative}} in conditional expression should have the same type, found {}, {}", e1.get_type(), e2.get_type()),
                     })?;
 
-                let kind = match kind {
-                    crate::absy::ConditionalKind::IfElse => {
-                        crate::typed_absy::ConditionalKind::IfElse
-                    }
-                    crate::absy::ConditionalKind::Ternary => {
-                        crate::typed_absy::ConditionalKind::Ternary
-                    }
-                };
-
                 match condition_checked {
                     TypedExpression::Boolean(condition) => {
                         match (consequence_checked, alternative_checked) {
                             (TypedExpression::FieldElement(consequence), TypedExpression::FieldElement(alternative)) => {
-                                Ok(FieldElementExpression::conditional(condition, consequence, alternative, kind).into())
+                                Ok(FieldElementExpression::conditional(condition, consequence, alternative).into())
                             },
                             (TypedExpression::Boolean(consequence), TypedExpression::Boolean(alternative)) => {
-                                Ok(BooleanExpression::conditional(condition, consequence, alternative, kind).into())
+                                Ok(BooleanExpression::conditional(condition, consequence, alternative).into())
                             },
                             (TypedExpression::Array(consequence), TypedExpression::Array(alternative)) => {
-                                Ok(ArrayExpression::conditional(condition, consequence, alternative, kind).into())
+                                Ok(ArrayExpression::conditional(condition, consequence, alternative).into())
                             },
                             (TypedExpression::Struct(consequence), TypedExpression::Struct(alternative)) => {
-                                Ok(StructExpression::conditional(condition, consequence, alternative, kind).into())
+                                Ok(StructExpression::conditional(condition, consequence, alternative).into())
                             },
                             (TypedExpression::Uint(consequence), TypedExpression::Uint(alternative)) => {
-                                Ok(UExpression::conditional(condition, consequence, alternative, kind).into())
+                                Ok(UExpression::conditional(condition, consequence, alternative).into())
                             },
                             (TypedExpression::Int(consequence), TypedExpression::Int(alternative)) => {
-                                Ok(IntExpression::conditional(condition, consequence, alternative, kind).into())
+                                Ok(IntExpression::conditional(condition, consequence, alternative).into())
                             },
                             (c, a) => Err(ErrorInner {
                                 pos: Some(pos),

zokrates_core/src/static_analysis/branch_isolator.rs

@@ -28,7 +28,6 @@ impl<'ast, T: Field> Folder<'ast, T> for Isolator {
             self.fold_boolean_expression(*e.condition),
             E::block(vec![], e.consequence.fold(self)),
             E::block(vec![], e.alternative.fold(self)),
-            e.kind,
         ))
     }
 }

zokrates_core/src/static_analysis/condition_redefiner.rs

@@ -81,7 +81,6 @@ impl<'ast, T: Field> Folder<'ast, T> for ConditionRedefiner<'ast, T> {
             condition,
             consequence,
             alternative,
-            e.kind,
         ))
     }
 }

zokrates_core/src/static_analysis/propagation.rs

@@ -209,7 +209,7 @@ impl<'ast, 'a, T: Field> ResultFolder<'ast, T> for Propagator<'ast, 'a, T> {
                     ConditionalOrExpression::Expression(consequence.into_inner())
                 }
                 (condition, consequence, alternative) => ConditionalOrExpression::Conditional(
-                    ConditionalExpression::new(condition, consequence, alternative, e.kind),
+                    ConditionalExpression::new(condition, consequence, alternative),
                 ),
             },
         )

zokrates_core/src/static_analysis/variable_write_remover.rs

@@ -73,7 +73,6 @@ impl<'ast> VariableWriteRemover {
                                         ),
                                             },
                                             ArrayExpression::select(base.clone(), i),
-                                            ConditionalKind::IfElse,
                                         )
                                         .into(),
                                         Type::Struct(..) => StructExpression::conditional(
@@ -94,7 +93,6 @@ impl<'ast> VariableWriteRemover {
                                         ),
                                             },
                                             StructExpression::select(base.clone(), i),
-                                            ConditionalKind::IfElse,
                                         )
                                         .into(),
                                         Type::Tuple(..) => TupleExpression::conditional(
@@ -115,7 +113,6 @@ impl<'ast> VariableWriteRemover {
                                         ),
                                             },
                                             TupleExpression::select(base.clone(), i),
-                                            ConditionalKind::IfElse,
                                         )
                                         .into(),
                                         Type::FieldElement => FieldElementExpression::conditional(
@@ -137,7 +134,6 @@ impl<'ast> VariableWriteRemover {
                                         ),
                                             },
                                             FieldElementExpression::select(base.clone(), i),
-                                            ConditionalKind::IfElse,
                                         )
                                         .into(),
                                         Type::Boolean => BooleanExpression::conditional(
@@ -158,7 +154,6 @@ impl<'ast> VariableWriteRemover {
                                         ),
                                             },
                                             BooleanExpression::select(base.clone(), i),
-                                            ConditionalKind::IfElse,
                                         )
                                         .into(),
                                         Type::Uint(..) => UExpression::conditional(
@@ -179,7 +174,6 @@ impl<'ast> VariableWriteRemover {
                                         ),
                                             },
                                             UExpression::select(base.clone(), i),
-                                            ConditionalKind::IfElse,
                                         )
                                         .into(),
                                     })

zokrates_core/src/typed_absy/folder.rs

@@ -749,7 +749,6 @@ pub fn fold_conditional_expression<
         f.fold_boolean_expression(*e.condition),
         e.consequence.fold(f),
         e.alternative.fold(f),
-        e.kind,
     ))
 }
 

zokrates_core/src/typed_absy/integer.rs

@@ -452,7 +452,6 @@ impl<'ast, T: Field> FieldElementExpression<'ast, T> {
                 *c.condition,
                 Self::try_from_int(*c.consequence)?,
                 Self::try_from_int(*c.alternative)?,
-                c.kind,
             ))),
             IntExpression::Select(select) => {
                 let array = *select.array;
@@ -572,7 +571,6 @@ impl<'ast, T: Field> UExpression<'ast, T> {
                 *c.condition,
                 Self::try_from_int(*c.consequence, bitwidth)?,
                 Self::try_from_int(*c.alternative, bitwidth)?,
-                c.kind,
             )),
             Select(select) => {
                 let array = *select.array;

zokrates_core/src/typed_absy/mod.rs

@@ -1016,50 +1016,30 @@ impl<'ast, T: fmt::Display, E> fmt::Display for ElementExpression<'ast, T, E> {
     }
 }
 
-#[derive(Debug, Clone, PartialEq, Hash, Eq, PartialOrd, Ord)]
-pub enum ConditionalKind {
-    IfElse,
-    Ternary,
-}
-
 #[derive(Debug, Clone, PartialEq, Hash, Eq, PartialOrd, Ord)]
 pub struct ConditionalExpression<'ast, T, E> {
     pub condition: Box<BooleanExpression<'ast, T>>,
     pub consequence: Box<E>,
     pub alternative: Box<E>,
-    pub kind: ConditionalKind,
 }
 
 impl<'ast, T, E> ConditionalExpression<'ast, T, E> {
-    pub fn new(
+    pub fn new(condition: BooleanExpression<'ast, T>, consequence: E, alternative: E) -> Self {
-        condition: BooleanExpression<'ast, T>,
-        consequence: E,
-        alternative: E,
-        kind: ConditionalKind,
-    ) -> Self {
         ConditionalExpression {
             condition: box condition,
             consequence: box consequence,
             alternative: box alternative,
-            kind,
         }
     }
 }
 
 impl<'ast, T: fmt::Display, E: fmt::Display> fmt::Display for ConditionalExpression<'ast, T, E> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        match self.kind {
+        write!(
-            ConditionalKind::IfElse => write!(
+            f,
-                f,
+            "{} ? {} : {}",
-                "if {} then {} else {} fi",
+            self.condition, self.consequence, self.alternative
-                self.condition, self.consequence, self.alternative
+        )
-            ),
-            ConditionalKind::Ternary => write!(
-                f,
-                "{} ? {} : {}",
-                self.condition, self.consequence, self.alternative
-            ),
-        }
     }
 }
 
@@ -2010,7 +1990,6 @@ pub trait Conditional<'ast, T> {
         condition: BooleanExpression<'ast, T>,
         consequence: Self,
         alternative: Self,
-        kind: ConditionalKind,
     ) -> Self;
 }
 
@@ -2019,13 +1998,11 @@ impl<'ast, T> Conditional<'ast, T> for FieldElementExpression<'ast, T> {
         condition: BooleanExpression<'ast, T>,
         consequence: Self,
         alternative: Self,
-        kind: ConditionalKind,
     ) -> Self {
         FieldElementExpression::Conditional(ConditionalExpression::new(
             condition,
             consequence,
             alternative,
-            kind,
         ))
     }
 }
@@ -2035,13 +2012,11 @@ impl<'ast, T> Conditional<'ast, T> for IntExpression<'ast, T> {
         condition: BooleanExpression<'ast, T>,
         consequence: Self,
         alternative: Self,
-        kind: ConditionalKind,
     ) -> Self {
         IntExpression::Conditional(ConditionalExpression::new(
             condition,
             consequence,
             alternative,
-            kind,
         ))
     }
 }
@@ -2051,13 +2026,11 @@ impl<'ast, T> Conditional<'ast, T> for BooleanExpression<'ast, T> {
         condition: BooleanExpression<'ast, T>,
         consequence: Self,
         alternative: Self,
-        kind: ConditionalKind,
     ) -> Self {
         BooleanExpression::Conditional(ConditionalExpression::new(
             condition,
             consequence,
             alternative,
-            kind,
         ))
     }
 }
@@ -2067,7 +2040,6 @@ impl<'ast, T> Conditional<'ast, T> for UExpression<'ast, T> {
         condition: BooleanExpression<'ast, T>,
         consequence: Self,
         alternative: Self,
-        kind: ConditionalKind,
     ) -> Self {
         let bitwidth = consequence.bitwidth;
 
@@ -2075,7 +2047,6 @@ impl<'ast, T> Conditional<'ast, T> for UExpression<'ast, T> {
             condition,
             consequence,
             alternative,
-            kind,
         ))
         .annotate(bitwidth)
     }
@@ -2086,7 +2057,6 @@ impl<'ast, T: Clone> Conditional<'ast, T> for ArrayExpression<'ast, T> {
         condition: BooleanExpression<'ast, T>,
         consequence: Self,
         alternative: Self,
-        kind: ConditionalKind,
     ) -> Self {
         let ty = consequence.inner_type().clone();
         let size = consequence.size();
@@ -2094,7 +2064,6 @@ impl<'ast, T: Clone> Conditional<'ast, T> for ArrayExpression<'ast, T> {
             condition,
             consequence,
             alternative,
-            kind,
         ))
         .annotate(ty, size)
     }
@@ -2105,14 +2074,12 @@ impl<'ast, T: Clone> Conditional<'ast, T> for StructExpression<'ast, T> {
         condition: BooleanExpression<'ast, T>,
         consequence: Self,
         alternative: Self,
-        kind: ConditionalKind,
     ) -> Self {
         let ty = consequence.ty().clone();
         StructExpressionInner::Conditional(ConditionalExpression::new(
             condition,
             consequence,
             alternative,
-            kind,
         ))
         .annotate(ty)
     }
@@ -2123,14 +2090,12 @@ impl<'ast, T: Clone> Conditional<'ast, T> for TupleExpression<'ast, T> {
         condition: BooleanExpression<'ast, T>,
         consequence: Self,
         alternative: Self,
-        kind: ConditionalKind,
     ) -> Self {
         let ty = consequence.ty().clone();
         TupleExpressionInner::Conditional(ConditionalExpression::new(
             condition,
             consequence,
             alternative,
-            kind,
         ))
         .annotate(ty)
     }

zokrates_core/src/typed_absy/result_folder.rs

@@ -822,7 +822,6 @@ pub fn fold_conditional_expression<
             f.fold_boolean_expression(*e.condition)?,
             e.consequence.fold(f)?,
             e.alternative.fold(f)?,
-            e.kind,
         ),
     ))
 }

zokrates_parser/src/zokrates.pest

@@ -54,17 +54,16 @@ vis = { vis_private | vis_public }
 
 // Statements
 statement = { (iteration_statement // does not require semicolon
-              | (return_statement
+              | ((return_statement
                 | definition_statement
-                | expression_statement
+                | assertion_statement
-                ) ~ semicolon
+                ) ~ semicolon)) ~ NEWLINE* }
-            ) ~ NEWLINE* }
 
 block_statement = _{ "{" ~ NEWLINE* ~ statement* ~ NEWLINE* ~ "}" }
 iteration_statement = { "for" ~ typed_identifier ~ "in" ~ expression ~ ".." ~ expression ~ block_statement }
-return_statement = { "return" ~ expression_list}
+return_statement = { "return" ~ expression_list }
 definition_statement = { typed_identifier_or_assignee_list ~ "=" ~ expression } // declare and assign, so only identifiers are allowed, unlike `assignment_statement`
-expression_statement = {"assert" ~ "(" ~ expression ~ ("," ~ quoted_string)? ~ ")"}
+assertion_statement = {"assert" ~ "(" ~ expression ~ ("," ~ quoted_string)? ~ ")"}
 
 typed_identifier_or_assignee_list = _{ typed_identifier_or_assignee ~ ("," ~ typed_identifier_or_assignee)* }
 typed_identifier_or_assignee = { typed_identifier | assignee } // we don't use { ty? ~ identifier } as with a single token, it gets parsed as `ty` but we want `identifier`
@@ -76,7 +75,7 @@ expression = { unaried_term ~ (op_binary ~ unaried_term)* }
 unaried_term = { op_unary? ~ powered_term }
 powered_term = { postfixed_term ~ (op_pow ~ exponent_expression)? }
 postfixed_term = { term ~ access* }
-term = { ("(" ~ expression ~ ")") | inline_tuple_expression | inline_struct_expression | if_else_expression | primary_expression | inline_array_expression | array_initializer_expression }
+term = { ("(" ~ expression ~ ")") | inline_tuple_expression | inline_struct_expression | primary_expression | inline_array_expression | array_initializer_expression }
 spread = { "..." ~ expression }
 range = { from_expression? ~ ".." ~ to_expression? }
 from_expression = { expression }
@@ -87,8 +86,6 @@ inline_tuple_empty_expression_inner = _{ "" }
 inline_tuple_single_expression_inner = _{ expression ~ "," }
 inline_tuple_multiple_expression_inner = _{ expression ~ ("," ~ expression)+ ~ ","? }
 
-if_else_expression = { "if" ~ expression ~ "then" ~ expression ~ "else" ~ expression ~ "fi"}
-
 access = { array_access | call_access | dot_access }
 array_access = { "[" ~ range_or_expression ~ "]" }
 call_access = { ("::" ~ explicit_generics)? ~ "(" ~ arguments ~ ")" }

zokrates_pest_ast/src/lib.rs

@@ -13,7 +13,7 @@ pub use ast::{
     BinaryOperator, CallAccess, ConstantDefinition, ConstantGenericValue, DecimalLiteralExpression,
     DecimalNumber, DecimalSuffix, DefinitionStatement, ExplicitGenerics, Expression, FieldType,
     File, FromExpression, FunctionDefinition, HexLiteralExpression, HexNumberExpression,
-    IdentifierExpression, IdentifierOrDecimal, IfElseExpression, ImportDirective, ImportSymbol,
+    IdentifierExpression, IdentifierOrDecimal, ImportDirective, ImportSymbol,
     InlineArrayExpression, InlineStructExpression, InlineStructMember, InlineTupleExpression,
     IterationStatement, LiteralExpression, Parameter, PostfixExpression, Range, RangeOrExpression,
     ReturnStatement, Span, Spread, SpreadOrExpression, Statement, StructDefinition, StructField,
@@ -384,7 +384,7 @@ mod ast {
     }
 
     #[derive(Debug, FromPest, PartialEq, Clone)]
-    #[pest_ast(rule(Rule::expression_statement))]
+    #[pest_ast(rule(Rule::assertion_statement))]
     pub struct AssertionStatement<'ast> {
         pub expression: Expression<'ast>,
         pub message: Option<AnyString<'ast>>,
@@ -437,7 +437,6 @@ mod ast {
     #[derive(Debug, PartialEq, Clone)]
     pub enum Expression<'ast> {
         Ternary(TernaryExpression<'ast>),
-        IfElse(IfElseExpression<'ast>),
         Binary(BinaryExpression<'ast>),
         Unary(UnaryExpression<'ast>),
         Postfix(PostfixExpression<'ast>),
@@ -454,7 +453,6 @@ mod ast {
     pub enum Term<'ast> {
         Expression(Expression<'ast>),
         InlineStruct(InlineStructExpression<'ast>),
-        IfElse(IfElseExpression<'ast>),
         Primary(PrimaryExpression<'ast>),
         InlineArray(InlineArrayExpression<'ast>),
         InlineTuple(InlineTupleExpression<'ast>),
@@ -571,7 +569,6 @@ mod ast {
         fn from(t: Term<'ast>) -> Self {
             match t {
                 Term::Expression(e) => e,
-                Term::IfElse(e) => Expression::IfElse(e),
                 Term::Primary(e) => e.into(),
                 Term::InlineArray(e) => Expression::InlineArray(e),
                 Term::InlineTuple(e) => Expression::InlineTuple(e),
@@ -814,31 +811,7 @@ mod ast {
         pub span: Span<'ast>,
     }
 
-    #[derive(Debug, FromPest, PartialEq, Clone)]
-    #[pest_ast(rule(Rule::if_else_expression))]
-    pub struct IfElseExpression<'ast> {
-        pub condition: Box<Expression<'ast>>,
-        pub consequence: Box<Expression<'ast>>,
-        pub alternative: Box<Expression<'ast>>,
-        #[pest_ast(outer())]
-        pub span: Span<'ast>,
-    }
-
     impl<'ast> Expression<'ast> {
-        pub fn if_else(
-            condition: Box<Expression<'ast>>,
-            consequence: Box<Expression<'ast>>,
-            alternative: Box<Expression<'ast>>,
-            span: Span<'ast>,
-        ) -> Self {
-            Expression::IfElse(IfElseExpression {
-                condition,
-                consequence,
-                alternative,
-                span,
-            })
-        }
-
         pub fn ternary(
             condition: Box<Expression<'ast>>,
             consequence: Box<Expression<'ast>>,
@@ -873,7 +846,6 @@ mod ast {
                 Expression::Identifier(i) => &i.span,
                 Expression::Literal(c) => c.span(),
                 Expression::Ternary(t) => &t.span,
-                Expression::IfElse(ie) => &ie.span,
                 Expression::Postfix(p) => &p.span,
                 Expression::InlineArray(a) => &a.span,
                 Expression::InlineStruct(s) => &s.span,
@@ -1291,7 +1263,7 @@ mod tests {
     #[test]
     fn ternary() {
         let source = r#"import "foo"
-                def main() -> (field): return if 1 then 2 else 3 fi
+                def main() -> (field): return 1 ? 2 : 3
 "#;
         assert_eq!(
             generate_ast(source),
@@ -1317,7 +1289,7 @@ mod tests {
                             span: Span::new(source, 44, 49).unwrap()
                         }))],
                         statements: vec![Statement::Return(ReturnStatement {
-                            expressions: vec![Expression::if_else(
+                            expressions: vec![Expression::ternary(
                                 Box::new(Expression::Literal(LiteralExpression::DecimalLiteral(
                                     DecimalLiteralExpression {
                                         suffix: None,