1 files changed, 55 insertions, 0 deletions
diff --git a/crates/cli/src/value_parse.rs b/crates/cli/src/value_parse.rs
new file mode 100644
index 0000000..f64d335
--- /dev/null
+++ b/crates/cli/src/value_parse.rs
@@ -0,0 +1,55 @@
+use eyre::{Result, bail};
+use tinywasm::types::{FuncType, WasmType, WasmValue};
+
+use crate::output::format_wasm_type;
+
+pub fn parse_invocation_args(ty: &FuncType, args: &[String]) -> Result<Vec<WasmValue>> {
+    if args.len() != ty.params().len() {
+        bail!("wrong number of arguments: expected {}, got {}", ty.params().len(), args.len())
+    }
+
+    ty.params().iter().enumerate().map(|(idx, param_ty)| parse_arg(idx, *param_ty, &args[idx])).collect()
+}
+
+fn parse_arg(index: usize, ty: WasmType, value: &str) -> Result<WasmValue> {
+    let parsed = match ty {
+        WasmType::I32 => value.parse::<i32>().map(WasmValue::from).map_err(|e| format_error(index, ty, value, e))?,
+        WasmType::I64 => value.parse::<i64>().map(WasmValue::from).map_err(|e| format_error(index, ty, value, e))?,
+        WasmType::F32 => value.parse::<f32>().map(WasmValue::from).map_err(|e| format_error(index, ty, value, e))?,
+        WasmType::F64 => value.parse::<f64>().map(WasmValue::from).map_err(|e| format_error(index, ty, value, e))?,
+        WasmType::V128 => value.parse::<i128>().map(WasmValue::from).map_err(|e| format_error(index, ty, value, e))?,
+        WasmType::RefFunc | WasmType::RefExtern => {
+            bail!(
+                "unsupported CLI argument type at position {}: {}; use the embedding API for reference values",
+                index + 1,
+                format_wasm_type(ty)
+            )
+        }
+    };
+
+    Ok(parsed)
+}
+
+fn format_error(index: usize, ty: WasmType, value: &str, error: impl core::fmt::Display) -> eyre::Report {
+    eyre::eyre!("failed to parse argument {} as {} from `{value}`: {error}", index + 1, format_wasm_type(ty))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn parses_numeric_args() {
+        let ty = FuncType::new(&[WasmType::I32, WasmType::F64], &[WasmType::I32]);
+        let args = vec!["1".to_string(), "2.5".to_string()];
+        let parsed = parse_invocation_args(&ty, &args).unwrap();
+        assert_eq!(parsed, vec![WasmValue::I32(1), WasmValue::F64(2.5)]);
+    }
+
+    #[test]
+    fn rejects_wrong_arity() {
+        let ty = FuncType::new(&[WasmType::I32], &[]);
+        let err = parse_invocation_args(&ty, &[]).unwrap_err();
+        assert!(err.to_string().contains("wrong number of arguments"));
+    }
+}