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v/vlib/toml/ast/walker/walker.v

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module walker
import toml.ast
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// Visitor defines a visit method which is invoked by the walker on each Value node it encounters.
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pub interface Visitor {
visit(value &ast.Value) ?
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}
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// Modifier defines a modify method which is invoked by the walker on each Value node it encounters.
pub interface Modifier {
modify(mut value ast.Value) ?
}
pub type InspectorFn = fn (value &ast.Value, data voidptr) ?
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struct Inspector {
inspector_callback InspectorFn
mut:
data voidptr
}
pub fn (i &Inspector) visit(value &ast.Value) ? {
i.inspector_callback(value, i.data) or { return err }
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}
// inspect traverses and checks the AST Value node on a depth-first order and based on the data given
pub fn inspect(value &ast.Value, data voidptr, inspector_callback InspectorFn) ? {
walk(Inspector{inspector_callback, data}, value) ?
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}
// walk traverses the AST using the given visitor
pub fn walk(visitor Visitor, value &ast.Value) ? {
if value is map[string]ast.Value {
value_map := value as map[string]ast.Value
for _, val in value_map {
walk(visitor, &val) ?
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}
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}
if value is []ast.Value {
value_array := value as []ast.Value
for val in value_array {
walk(visitor, &val) ?
}
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} else {
visitor.visit(value) ?
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}
}
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// walk_and_modify traverses the AST using the given modifier and lets the visitor
// modify the contents.
pub fn walk_and_modify(modifier Modifier, mut value ast.Value) ? {
if value is map[string]ast.Value {
mut value_map := value as map[string]ast.Value
for _, mut val in value_map {
walk_and_modify(modifier, mut &val) ?
}
}
if value is []ast.Value {
mut value_array := value as []ast.Value
for mut val in value_array {
walk_and_modify(modifier, mut &val) ?
}
} else {
modifier.modify(mut value) ?
}
}