Split up `model` module

1 files changed, 276 insertions, 0 deletions

diff --git a/src/eval/methods.rs b/src/eval/methods.rs
new file mode 100644
index 00000000..dcb1ca31
--- /dev/null
+++ b/src/eval/methods.rs
@@ -0,0 +1,276 @@
+//! Methods on values.
+
+use ecow::EcoString;
+
+use super::{Args, Str, Value, Vm};
+use crate::diag::{At, SourceResult};
+use crate::syntax::Span;
+
+/// Call a method on a value.
+pub fn call(
+    vm: &mut Vm,
+    value: Value,
+    method: &str,
+    mut args: Args,
+    span: Span,
+) -> SourceResult<Value> {
+    let name = value.type_name();
+    let missing = || Err(missing_method(name, method)).at(span);
+
+    let output = match value {
+        Value::Color(color) => match method {
+            "lighten" => Value::Color(color.lighten(args.expect("amount")?)),
+            "darken" => Value::Color(color.darken(args.expect("amount")?)),
+            "negate" => Value::Color(color.negate()),
+            _ => return missing(),
+        },
+
+        Value::Str(string) => match method {
+            "len" => Value::Int(string.len() as i64),
+            "first" => Value::Str(string.first().at(span)?),
+            "last" => Value::Str(string.last().at(span)?),
+            "at" => Value::Str(string.at(args.expect("index")?).at(span)?),
+            "slice" => {
+                let start = args.expect("start")?;
+                let mut end = args.eat()?;
+                if end.is_none() {
+                    end = args.named("count")?.map(|c: i64| start + c);
+                }
+                Value::Str(string.slice(start, end).at(span)?)
+            }
+            "clusters" => Value::Array(string.clusters()),
+            "codepoints" => Value::Array(string.codepoints()),
+            "contains" => Value::Bool(string.contains(args.expect("pattern")?)),
+            "starts-with" => Value::Bool(string.starts_with(args.expect("pattern")?)),
+            "ends-with" => Value::Bool(string.ends_with(args.expect("pattern")?)),
+            "find" => {
+                string.find(args.expect("pattern")?).map_or(Value::None, Value::Str)
+            }
+            "position" => string
+                .position(args.expect("pattern")?)
+                .map_or(Value::None, Value::Int),
+            "match" => string
+                .match_(args.expect("pattern")?)
+                .map_or(Value::None, Value::Dict),
+            "matches" => Value::Array(string.matches(args.expect("pattern")?)),
+            "replace" => {
+                let pattern = args.expect("pattern")?;
+                let with = args.expect("replacement string")?;
+                let count = args.named("count")?;
+                Value::Str(string.replace(pattern, with, count))
+            }
+            "trim" => {
+                let pattern = args.eat()?;
+                let at = args.named("at")?;
+                let repeat = args.named("repeat")?.unwrap_or(true);
+                Value::Str(string.trim(pattern, at, repeat))
+            }
+            "split" => Value::Array(string.split(args.eat()?)),
+            _ => return missing(),
+        },
+
+        Value::Array(array) => match method {
+            "len" => Value::Int(array.len()),
+            "first" => array.first().at(span)?.clone(),
+            "last" => array.last().at(span)?.clone(),
+            "at" => array.at(args.expect("index")?).at(span)?.clone(),
+            "slice" => {
+                let start = args.expect("start")?;
+                let mut end = args.eat()?;
+                if end.is_none() {
+                    end = args.named("count")?.map(|c: i64| start + c);
+                }
+                Value::Array(array.slice(start, end).at(span)?)
+            }
+            "contains" => Value::Bool(array.contains(&args.expect("value")?)),
+            "find" => array.find(vm, args.expect("function")?)?.unwrap_or(Value::None),
+            "position" => array
+                .position(vm, args.expect("function")?)?
+                .map_or(Value::None, Value::Int),
+            "filter" => Value::Array(array.filter(vm, args.expect("function")?)?),
+            "map" => Value::Array(array.map(vm, args.expect("function")?)?),
+            "fold" => {
+                array.fold(vm, args.expect("initial value")?, args.expect("function")?)?
+            }
+            "any" => Value::Bool(array.any(vm, args.expect("function")?)?),
+            "all" => Value::Bool(array.all(vm, args.expect("function")?)?),
+            "flatten" => Value::Array(array.flatten()),
+            "rev" => Value::Array(array.rev()),
+            "join" => {
+                let sep = args.eat()?;
+                let last = args.named("last")?;
+                array.join(sep, last).at(span)?
+            }
+            "sorted" => Value::Array(array.sorted().at(span)?),
+            _ => return missing(),
+        },
+
+        Value::Dict(dict) => match method {
+            "len" => Value::Int(dict.len()),
+            "at" => dict.at(&args.expect::<Str>("key")?).cloned().at(span)?,
+            "keys" => Value::Array(dict.keys()),
+            "values" => Value::Array(dict.values()),
+            "pairs" => Value::Array(dict.pairs()),
+            _ => return missing(),
+        },
+
+        Value::Func(func) => match method {
+            "with" => Value::Func(func.with(args.take())),
+            "where" => Value::dynamic(func.where_(&mut args).at(span)?),
+            _ => return missing(),
+        },
+
+        Value::Args(args) => match method {
+            "pos" => Value::Array(args.to_pos()),
+            "named" => Value::Dict(args.to_named()),
+            _ => return missing(),
+        },
+
+        _ => return missing(),
+    };
+
+    args.finish()?;
+    Ok(output)
+}
+
+/// Call a mutating method on a value.
+pub fn call_mut(
+    value: &mut Value,
+    method: &str,
+    mut args: Args,
+    span: Span,
+) -> SourceResult<Value> {
+    let name = value.type_name();
+    let missing = || Err(missing_method(name, method)).at(span);
+    let mut output = Value::None;
+
+    match value {
+        Value::Array(array) => match method {
+            "push" => array.push(args.expect("value")?),
+            "pop" => output = array.pop().at(span)?,
+            "insert" => {
+                array.insert(args.expect("index")?, args.expect("value")?).at(span)?
+            }
+            "remove" => output = array.remove(args.expect("index")?).at(span)?,
+            _ => return missing(),
+        },
+
+        Value::Dict(dict) => match method {
+            "insert" => dict.insert(args.expect::<Str>("key")?, args.expect("value")?),
+            "remove" => {
+                output = dict.remove(&args.expect::<EcoString>("key")?).at(span)?
+            }
+            _ => return missing(),
+        },
+
+        _ => return missing(),
+    }
+
+    args.finish()?;
+    Ok(output)
+}
+
+/// Call an accessor method on a value.
+pub fn call_access<'a>(
+    value: &'a mut Value,
+    method: &str,
+    mut args: Args,
+    span: Span,
+) -> SourceResult<&'a mut Value> {
+    let name = value.type_name();
+    let missing = || Err(missing_method(name, method)).at(span);
+
+    let slot = match value {
+        Value::Array(array) => match method {
+            "first" => array.first_mut().at(span)?,
+            "last" => array.last_mut().at(span)?,
+            "at" => array.at_mut(args.expect("index")?).at(span)?,
+            _ => return missing(),
+        },
+        Value::Dict(dict) => match method {
+            "at" => dict.at_mut(&args.expect::<Str>("key")?).at(span)?,
+            _ => return missing(),
+        },
+        _ => return missing(),
+    };
+
+    args.finish()?;
+    Ok(slot)
+}
+
+/// Whether a specific method is mutating.
+pub fn is_mutating(method: &str) -> bool {
+    matches!(method, "push" | "pop" | "insert" | "remove")
+}
+
+/// Whether a specific method is an accessor.
+pub fn is_accessor(method: &str) -> bool {
+    matches!(method, "first" | "last" | "at")
+}
+
+/// The missing method error message.
+#[cold]
+fn missing_method(type_name: &str, method: &str) -> String {
+    format!("type {type_name} has no method `{method}`")
+}
+
+/// List the available methods for a type and whether they take arguments.
+pub fn methods_on(type_name: &str) -> &[(&'static str, bool)] {
+    match type_name {
+        "color" => &[("lighten", true), ("darken", true), ("negate", false)],
+        "string" => &[
+            ("len", false),
+            ("at", true),
+            ("clusters", false),
+            ("codepoints", false),
+            ("contains", true),
+            ("ends-with", true),
+            ("find", true),
+            ("first", false),
+            ("last", false),
+            ("match", true),
+            ("matches", true),
+            ("position", true),
+            ("replace", true),
+            ("slice", true),
+            ("split", true),
+            ("starts-with", true),
+            ("trim", true),
+        ],
+        "array" => &[
+            ("all", true),
+            ("any", true),
+            ("at", true),
+            ("contains", true),
+            ("filter", true),
+            ("find", true),
+            ("first", false),
+            ("flatten", false),
+            ("fold", true),
+            ("insert", true),
+            ("join", true),
+            ("last", false),
+            ("len", false),
+            ("map", true),
+            ("pop", false),
+            ("position", true),
+            ("push", true),
+            ("remove", true),
+            ("rev", false),
+            ("slice", true),
+            ("sorted", false),
+        ],
+        "dictionary" => &[
+            ("at", true),
+            ("insert", true),
+            ("keys", false),
+            ("len", false),
+            ("pairs", false),
+            ("remove", true),
+            ("values", false),
+        ],
+        "function" => &[("where", true), ("with", true)],
+        "arguments" => &[("named", false), ("pos", false)],
+        _ => &[],
+    }
+}