feat: add a logger hook

components/clarity-repl/src/repl/logger_hook.rs

@@ -0,0 +1,59 @@
+use clarity::vm::errors::Error;
+use clarity::vm::functions::NativeFunctions;
+use clarity::vm::representations::Span;
+use clarity::vm::types::QualifiedContractIdentifier;
+use clarity::vm::{
+    contexts::{Environment, LocalContext},
+    types::Value,
+    EvalHook, ExecutionResult, SymbolicExpression,
+    SymbolicExpressionType::List,
+};
+
+pub struct ContractLog {
+    contract_id: QualifiedContractIdentifier,
+    span: Span,
+    result: Value,
+}
+
+#[derive(Default)]
+pub struct LoggerHook {
+    logs: Vec<ContractLog>,
+}
+
+impl LoggerHook {
+    pub fn new() -> Self {
+        LoggerHook::default()
+    }
+}
+
+impl EvalHook for LoggerHook {
+    fn will_begin_eval(&mut self, _: &mut Environment, _: &LocalContext, _: &SymbolicExpression) {}
+
+    fn did_finish_eval(
+        &mut self,
+        env: &mut Environment,
+        _context: &LocalContext,
+        expr: &SymbolicExpression,
+        res: &Result<Value, Error>,
+    ) {
+        if let List(list) = &expr.expr {
+            if let Some((function_name, _args)) = list.split_first() {
+                if let Some(function_name) = function_name.match_atom() {
+                    if let Some(NativeFunctions::Print) =
+                        NativeFunctions::lookup_by_name(function_name)
+                    {
+                        if let Ok(value) = res {
+                            self.logs.push(ContractLog {
+                                contract_id: env.contract_context.contract_identifier.clone(),
+                                span: expr.span.clone(),
+                                result: value.clone(),
+                            });
+                        }
+                    }
+                }
+            }
+        }
+    }
+
+    fn did_complete(&mut self, _: Result<&mut ExecutionResult, String>) {}
+}

components/clarity-repl/src/repl/mod.rs

@@ -3,6 +3,7 @@ pub mod clarity_values;
 pub mod datastore;
 pub mod diagnostic;
 pub mod interpreter;
+pub mod logger_hook;
 pub mod session;
 pub mod settings;
 pub mod tracer;

components/clarity-repl/src/repl/session.rs

@@ -1,5 +1,6 @@
 use super::boot::{STACKS_BOOT_CODE_MAINNET, STACKS_BOOT_CODE_TESTNET};
 use super::diagnostic::output_diagnostic;
+use super::logger_hook::LoggerHook;
 use super::{ClarityCodeSource, ClarityContract, ClarityInterpreter, ContractDeployer};
 use crate::analysis::coverage::CoverageHook;
 use crate::repl::clarity_values::value_to_string;
@@ -1802,3 +1803,56 @@ mod tests {
         assert!(time_block_2 - time_block_1 == 600);
     }
 }
+#[cfg(test)]
+mod logger_hook_tests {
+
+    use crate::{repl::DEFAULT_EPOCH, test_fixtures::clarity_contract::ClarityContractBuilder};
+
+    use super::*;
+
+    #[test]
+    fn can_retrieve_print_values() {
+        let settings = SessionSettings::default();
+        let mut session = Session::new(settings);
+        session.start().expect("session could not start");
+        session.update_epoch(DEFAULT_EPOCH);
+
+        // session.deploy_contract(contract, eval_hooks, cost_track, test_name, ast)
+        let snippet = [
+            "(define-public (print-and-return (input (response uint uint)))",
+            "  (begin",
+            "    (match input x (print x) y (print y))",
+            "    input",
+            "  )",
+            ")",
+        ]
+        .join("\n");
+
+        let contract = ClarityContractBuilder::new().code_source(snippet).build();
+
+        let _ = session.deploy_contract(&contract, false, None);
+        let arg = SymbolicExpression::atom_value(Value::okay(Value::UInt(42)).unwrap());
+        let res = session.call_contract_fn(
+            "contract",
+            "print-and-return",
+            &[arg],
+            &session.get_tx_sender(),
+            false,
+            false,
+        );
+
+        println!("{:?}", res);
+
+        let arg = SymbolicExpression::atom_value(Value::error(Value::UInt(404)).unwrap());
+        let res = session.call_contract_fn(
+            "contract",
+            "print-and-return",
+            &[arg],
+            &session.get_tx_sender(),
+            false,
+            false,
+        );
+
+        println!("{:?}", res);
+    }
+}