use super::{call_args, custom, function, list, panic_expr, tuple};
use crate::plan::execution::lowering::graph::{DraftCursor, DraftFlow, DraftGraph, DraftString};
use crate::plan::execution::lowering::specialization::{Representability, StoredValueShape};
use crate::plan::{execution, module};
pub(in crate::plan::execution::lowering) fn string_expr(
expression: &module::StringExpr,
cursor: DraftCursor,
graph: &mut DraftGraph,
context: &mut super::super::LoweringContext,
) -> Representability<DraftFlow<DraftString>> {
use super::super::instruction::DraftStringInstruction as I;
use module::StringExprKind as E;
match expression.kind() {
E::Value(value) => {
let mut cursor = cursor;
let value = graph.string_instruction(&mut cursor, I::Value(value.clone()));
Representability::Inhabited(DraftFlow::value(cursor, value))
}
E::Constant(reference) => context.string_constant(reference).map(|id| {
let mut cursor = cursor;
let value = graph.string_instruction(
&mut cursor,
I::Constant(execution::constant::ConstantId::new(id.index())),
);
DraftFlow::value(cursor, value)
}),
E::LocalGet { local, name: _ } => {
let value = cursor.scope().string(super::super::local::LocalKey::new(
super::super::local::LocalKind::String,
local.0,
));
Representability::Inhabited(DraftFlow::value(cursor, value))
}
E::Call {
function,
args,
site,
} => call_args(args, cursor, graph, context).and_then(|flow| match flow {
DraftFlow::Diverged => Representability::Inhabited(DraftFlow::Diverged),
DraftFlow::Value {
mut cursor,
value: args,
} => context.string_function_id(function).map(|function| {
let value = graph.string_instruction(
&mut cursor,
I::Call {
function,
args,
site: site.clone(),
},
);
DraftFlow::value(cursor, value)
}),
}),
E::FunctionCall {
function: value,
args,
site,
} => {
function::string_function_expr(value, cursor, graph, context).and_then(
|flow| match flow {
DraftFlow::Diverged => Representability::Inhabited(DraftFlow::Diverged),
DraftFlow::Value {
cursor,
value: function,
} => call_args(args, cursor, graph, context).map(|flow| match flow {
DraftFlow::Diverged => DraftFlow::Diverged,
DraftFlow::Value {
mut cursor,
value: args,
} => {
let value = graph.string_instruction(
&mut cursor,
I::FunctionCall {
function: function.value().clone(),
args,
site: site.clone(),
},
);
DraftFlow::value(cursor, value)
}
}),
},
)
}
E::TupleIndex {
tuple: value,
index,
} => tuple::tuple_expr(value, cursor, graph, context).map(|flow| match flow {
DraftFlow::Diverged => DraftFlow::Diverged,
DraftFlow::Value {
mut cursor,
value: tuple,
} => {
let value = graph.string_instruction(
&mut cursor,
I::TupleIndex {
tuple,
index: *index,
},
);
DraftFlow::value(cursor, value)
}
}),
E::CustomField(access) => {
custom::custom_expr(access.source(), cursor, graph, context).map(|flow| match flow {
DraftFlow::Diverged => DraftFlow::Diverged,
DraftFlow::Value {
mut cursor,
value: source,
} => {
let value = graph.string_instruction(
&mut cursor,
I::CustomField {
source,
index: access.index(),
},
);
DraftFlow::value(cursor, value)
}
})
}
E::ListIndex { list: value, index } => {
list::string_list_expr(value, cursor, graph, context).map(|flow| match flow {
DraftFlow::Diverged => DraftFlow::Diverged,
DraftFlow::Value {
mut cursor,
value: list,
} => {
let value = graph.string_instruction(
&mut cursor,
I::ListIndex {
list: list.value().clone(),
index: *index,
},
);
DraftFlow::value(cursor, value)
}
})
}
E::Panic(value) => panic_expr(value, cursor, graph, context).map(|_| DraftFlow::Diverged),
E::Concatenate { left, right } => {
string_expr(left, cursor, graph, context).and_then(|flow| match flow {
DraftFlow::Diverged => Representability::Inhabited(DraftFlow::Diverged),
DraftFlow::Value {
cursor,
value: left,
} => string_expr(right, cursor, graph, context).map(|flow| match flow {
DraftFlow::Diverged => DraftFlow::Diverged,
DraftFlow::Value {
mut cursor,
value: right,
} => {
let value =
graph.string_instruction(&mut cursor, I::Concatenate { left, right });
DraftFlow::value(cursor, value)
}
}),
})
}
E::DropPrefix { value, prefix } => {
string_expr(value, cursor, graph, context).map(|flow| match flow {
DraftFlow::Diverged => DraftFlow::Diverged,
DraftFlow::Value { mut cursor, value } => {
let value = graph.string_instruction(
&mut cursor,
I::DropPrefix {
value,
prefix: prefix.clone(),
},
);
DraftFlow::value(cursor, value)
}
})
}
E::BoolCase {
subject,
true_,
false_,
} => super::bool_case(
subject,
cursor,
super::case_lowering(graph, context, StoredValueShape::String),
|cursor, graph, context| string_expr(true_, cursor, graph, context),
|cursor, graph, context| string_expr(false_, cursor, graph, context),
DraftString::from_ref,
),
E::IntCase {
subject,
clauses,
fallback,
} => super::int_case(
subject,
clauses,
fallback,
cursor,
super::case_lowering(graph, context, StoredValueShape::String),
string_expr,
DraftString::from_ref,
),
E::StringCase {
subject,
clauses,
fallback,
} => super::string_case(
subject,
clauses,
fallback,
cursor,
super::case_lowering(graph, context, StoredValueShape::String),
string_expr,
DraftString::from_ref,
),
E::FloatCase {
subject,
clauses,
fallback,
} => super::float_case(
subject,
clauses,
fallback,
cursor,
super::case_lowering(graph, context, StoredValueShape::String),
string_expr,
DraftString::from_ref,
),
E::Block { steps, return_ } => super::super::step::steps(steps, cursor, graph, context)
.and_then(|flow| match flow {
DraftFlow::Diverged => Representability::Inhabited(DraftFlow::Diverged),
DraftFlow::Value { cursor, value: () } => {
string_expr(return_, cursor, graph, context)
}
}),
}
}
#[cfg(test)]
mod tests {
use super::string_expr;
use crate::plan::execution::lowering::graph::draft::DraftGraphBuilder;
use crate::plan::execution::lowering::graph::{DraftFlow, DraftValueRef};
use crate::plan::execution::lowering::specialization::Representability;
use crate::plan::{
Expr, GenericExpr, GenericLocal, GenericLocalId, PanicExpr, PanicSite, Step, StringExpr,
TypeParameterId,
};
#[derive(Debug, PartialEq, Eq)]
enum FlowOutcome {
Uninhabited,
Diverged,
Value,
}
fn flow_outcome<T>(flow: Representability<DraftFlow<T>>) -> FlowOutcome {
match flow {
Representability::Uninhabited => FlowOutcome::Uninhabited,
Representability::Inhabited(DraftFlow::Diverged) => FlowOutcome::Diverged,
Representability::Inhabited(DraftFlow::Value { .. }) => FlowOutcome::Value,
}
}
#[test]
fn string_lowering_preserves_each_terminal_source_outcome() {
let parameter = TypeParameterId(0);
let expressions = [
(StringExpr::value("value".into()), FlowOutcome::Value),
(
StringExpr::drop_prefix(
StringExpr::panic(PanicExpr::panic_at(None, PanicSite::unknown())),
"prefix".into(),
),
FlowOutcome::Diverged,
),
(
StringExpr::block(
vec![Step::evaluate(Expr::generic(GenericExpr::local_get(
GenericLocal::new(GenericLocalId(0), parameter),
"value".into(),
)))],
StringExpr::value("unreachable".into()),
),
FlowOutcome::Uninhabited,
),
];
let mut context =
crate::plan::execution::lowering::test_support::lowering_context(Vec::new());
let (mut graph, cursor) =
DraftGraphBuilder::<DraftValueRef, ()>::new(Vec::new(), Vec::new());
for (expression, expected) in expressions {
let cursor = graph.empty_block(cursor.scope().clone());
assert_eq!(
flow_outcome(string_expr(&expression, cursor, &mut graph, &mut context)),
expected,
);
}
}
#[test]
fn string_concatenation_preserves_left_to_right_source_stops() {
for (expression, expected) in [
("failed(\"left\") <> failed(\"right\")", "panic: left"),
("\"left\" <> failed(\"right\")", "panic: right"),
(
"{ panic as \"left\" } <> { panic as \"right\" }",
"panic: left",
),
("\"left\" <> { panic as \"right\" }", "panic: right"),
] {
assert_eq!(run(expression), expected);
}
}
fn run(expression: &str) -> String {
let source = format!(
r#"
fn failed(message: String) -> String {{ panic as message }}
pub fn main() {{ {expression} }}
"#,
);
let typed = crate::compile_typed_module("main", "main.gleam", source.as_str())
.expect("source should compile");
let module = crate::plan_module(typed).expect("source should plan");
crate::run_main(
&crate::ExecutionPlan::from_module_plan(module),
&mut Vec::new(),
)
.unwrap_err()
.to_string()
}
}