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