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feat(stdlib): add fs_*/env_args/format builtins + my-cli argv forwarding #2

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Merged
hyperpolymath merged 1 commit into from
May 2, 2026
Merged

feat(stdlib): add fs_*/env_args/format builtins + my-cli argv forwarding #2

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12 changes: 10 additions & 2 deletions crates/my-cli/src/main.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -19,7 +19,12 @@ struct Cli {
#[derive(Subcommand)]
enum Commands {
/// Run a My Language file with the interpreter
Run { file: PathBuf },
Run {
file: PathBuf,
/// Args passed to the program (visible to env_args()). Use `--` to separate.
#[arg(trailing_var_arg = true, allow_hyphen_values = true)]
args: Vec<String>,
},

/// Parse a file and show the AST
Parse {
Expand Down Expand Up @@ -61,7 +66,10 @@ fn main() -> Result<()> {
let cli = Cli::parse();

match cli.command {
Commands::Run { file } => run_file(&file),
Commands::Run { file, args } => {
my_lang::stdlib::set_program_args(args);
run_file(&file)
}
Commands::Parse { file, output } => parse_file(&file, &output),
Commands::DumpSexpr { file } => parse_file(&file, "sexpr"),
Commands::Lex { file } => lex_file(&file),
Expand Down
203 changes: 203 additions & 0 deletions crates/my-lang/src/stdlib.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -5,6 +5,19 @@

use crate::interpreter::{NativeFunction, RuntimeError, Value};
use std::collections::HashMap;
use std::sync::OnceLock;

/// Program argv forwarded by the host (e.g. my-cli's `Run` command).
/// When set, `env_args()` returns these instead of `std::env::args().skip(1)`.
/// This lets `my run script.my -- --flag value` propagate `--flag value` to
/// the program without my-cli's clap consuming it.
static PROGRAM_ARGS: OnceLock<Vec<String>> = OnceLock::new();

/// Set the program argv visible to `env_args()`. Idempotent (first call wins).
/// Hosts (my-cli, embedders) call this before running a program.
pub fn set_program_args(args: Vec<String>) {
let _ = PROGRAM_ARGS.set(args);
}

/// Register all standard library functions into an environment
pub fn register_stdlib(define: &mut impl FnMut(String, Value)) {
Expand All @@ -25,6 +38,12 @@ pub fn register_stdlib(define: &mut impl FnMut(String, Value)) {

// Utility Functions
register_utility_functions(define);

// File System Functions (added 2026-04-30 per idaptik-port stdlib PR)
register_fs_functions(define);

// Environment Extras (env_args; complements existing env(name))
register_env_extras(define);
}

// ============================================================================
Expand Down Expand Up @@ -363,6 +382,63 @@ fn register_string_functions(define: &mut impl FnMut(String, Value)) {
},
}),
);

// format(template, args) - positional {} substitution; {{ and }} escape
define(
"format".to_string(),
Value::NativeFunction(NativeFunction {
name: "format".to_string(),
arity: 2,
func: |args| {
let template = match &args[0] {
Value::String(s) => s.clone(),
_ => {
return Err(RuntimeError::TypeError {
expected: "string".to_string(),
got: format!("{:?}", args[0]),
})
}
};
let values = match &args[1] {
Value::Array(a) => a.clone(),
_ => {
return Err(RuntimeError::TypeError {
expected: "array".to_string(),
got: format!("{:?}", args[1]),
})
}
};
let mut result = String::new();
let mut chars = template.chars().peekable();
let mut idx = 0usize;
while let Some(c) = chars.next() {
if c == '{' && chars.peek() == Some(&'{') {
chars.next();
result.push('{');
} else if c == '{' && chars.peek() == Some(&'}') {
chars.next();
if idx >= values.len() {
return Err(RuntimeError::Custom(format!(
"format: not enough args for placeholder #{}",
idx
)));
}
match &values[idx] {
Value::String(s) => result.push_str(s),
v => result.push_str(&format!("{}", v)),
}
idx += 1;
} else if c == '}' && chars.peek() == Some(&'}') {
chars.next();
result.push('}');
} else {
result.push(c);
}
}
Ok(Value::String(result))
},
}),
);
}

// ============================================================================
Expand Down Expand Up @@ -1293,6 +1369,125 @@ fn register_utility_functions(define: &mut impl FnMut(String, Value)) {
);
}

// ============================================================================
// FILE SYSTEM FUNCTIONS
// ============================================================================

fn register_fs_functions(define: &mut impl FnMut(String, Value)) {
// fs_write_file(path, content) - write content to path; auto-create parent dirs
define(
"fs_write_file".to_string(),
Value::NativeFunction(NativeFunction {
name: "fs_write_file".to_string(),
arity: 2,
func: |args| {
let (path, content) = match (&args[0], &args[1]) {
(Value::String(p), Value::String(c)) => (p.clone(), c.clone()),
_ => {
return Err(RuntimeError::TypeError {
expected: "string, string".to_string(),
got: format!("{:?}, {:?}", args[0], args[1]),
})
}
};
if let Some(parent) = std::path::Path::new(&path).parent() {
if !parent.as_os_str().is_empty() && !parent.exists() {
std::fs::create_dir_all(parent).map_err(|e| {
RuntimeError::Custom(format!(
"fs_write_file: create_dir_all({}) failed: {}",
parent.display(),
e
))
})?;
}
}
std::fs::write(&path, content).map_err(|e| {
RuntimeError::Custom(format!("fs_write_file({}) failed: {}", path, e))
})?;
Ok(Value::Unit)
},
}),
);

// fs_read_file(path) -> String
define(
"fs_read_file".to_string(),
Value::NativeFunction(NativeFunction {
name: "fs_read_file".to_string(),
arity: 1,
func: |args| match &args[0] {
Value::String(path) => std::fs::read_to_string(path).map(Value::String).map_err(
|e| RuntimeError::Custom(format!("fs_read_file({}) failed: {}", path, e)),
),
_ => Err(RuntimeError::TypeError {
expected: "string".to_string(),
got: format!("{:?}", args[0]),
}),
},
}),
);

// fs_create_dir_all(path) -> Unit
define(
"fs_create_dir_all".to_string(),
Value::NativeFunction(NativeFunction {
name: "fs_create_dir_all".to_string(),
arity: 1,
func: |args| match &args[0] {
Value::String(path) => std::fs::create_dir_all(path)
.map(|_| Value::Unit)
.map_err(|e| {
RuntimeError::Custom(format!("fs_create_dir_all({}) failed: {}", path, e))
}),
_ => Err(RuntimeError::TypeError {
expected: "string".to_string(),
got: format!("{:?}", args[0]),
}),
},
}),
);

// fs_exists(path) -> Bool
define(
"fs_exists".to_string(),
Value::NativeFunction(NativeFunction {
name: "fs_exists".to_string(),
arity: 1,
func: |args| match &args[0] {
Value::String(path) => Ok(Value::Bool(std::path::Path::new(path).exists())),
_ => Err(RuntimeError::TypeError {
expected: "string".to_string(),
got: format!("{:?}", args[0]),
}),
},
}),
);
}

// ============================================================================
// ENV EXTRAS
// ============================================================================

fn register_env_extras(define: &mut impl FnMut(String, Value)) {
// env_args() -> Array<String> - argv visible to the My program.
// Prefers host-supplied args (my-cli forwards trailing args after `--`);
// falls back to OS argv.skip(1) for backwards compat.
define(
"env_args".to_string(),
Value::NativeFunction(NativeFunction {
name: "env_args".to_string(),
arity: 0,
func: |_| {
let args: Vec<Value> = match PROGRAM_ARGS.get() {
Some(host_args) => host_args.iter().cloned().map(Value::String).collect(),
None => std::env::args().skip(1).map(Value::String).collect(),
};
Ok(Value::Array(args))
},
}),
);
}

/// Get a list of all stdlib function names
pub fn stdlib_functions() -> Vec<&'static str> {
vec![
Expand All @@ -1316,6 +1511,7 @@ pub fn stdlib_functions() -> Vec<&'static str> {
"str_ends_with",
"str_substring",
"char_at",
"format",
// Math
"abs",
"min",
Expand Down Expand Up @@ -1374,5 +1570,12 @@ pub fn stdlib_functions() -> Vec<&'static str> {
"random",
"random_int",
"env",
// FS
"fs_write_file",
"fs_read_file",
"fs_create_dir_all",
"fs_exists",
// Env extras
"env_args",
]
}
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