66 lines
2.9 KiB
Text
66 lines
2.9 KiB
Text
# eval.ludic - an expression's value, here
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function ui_eval(ui_st: mut UiState, x: UiExpr, e: UiEnv) -> Val {
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if x.op == X_LIT { return x.v }
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if x.op == X_NAME { return env_get(ui_st, e, x.s) }
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if x.op == X_MEMBER {
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let o = ui_eval(ui_st, x.a, e)
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if Value.kind(o) == 6 and Value.has(o, x.s) != 0 { return Value.get(o, x.s) }
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if Value.kind(o) == 5 and x.s == "length" { return uv_int(ui_st, Value.count(o)) }
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ui_err(ui_st, `.{x.s}: there is no such field`)
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return Value.null()
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}
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if x.op == X_INDEX { return Value.at(ui_eval(ui_st, x.a, e), Value.as_int(ui_eval(ui_st, x.b, e))) }
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if x.op == X_CALL { return ev_call(ui_st, x, e) }
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if x.op == X_NOT { return vl_bool(ui_st, not vl_truthy(ui_eval(ui_st, x.a, e))) }
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if x.op == X_NEG { return vl_arith(ui_st, "-", mm_ival(ui_st, 0), ui_eval(ui_st, x.a, e)) }
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if x.op == X_AND {
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if not vl_truthy(ui_eval(ui_st, x.a, e)) { return vl_bool(ui_st, false) }
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return vl_bool(ui_st, vl_truthy(ui_eval(ui_st, x.b, e)))
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}
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if x.op == X_OR {
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if vl_truthy(ui_eval(ui_st, x.a, e)) { return vl_bool(ui_st, true) }
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return vl_bool(ui_st, vl_truthy(ui_eval(ui_st, x.b, e)))
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}
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if x.op == X_COND {
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if vl_truthy(ui_eval(ui_st, x.a, e)) { return ui_eval(ui_st, x.b, e) }
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return ui_eval(ui_st, x.c, e)
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}
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if x.op == X_TEXT { return ev_text(ui_st, x, e) }
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return vl_binary(ui_st, x.s, ui_eval(ui_st, x.a, e), ui_eval(ui_st, x.b, e))
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}
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# a call: len() and range() are the template's own, anything else is the view's
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function ev_call(ui_st: mut UiState, x: UiExpr, e: UiEnv) -> Val {
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let depth = ui_st.ev_depth
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while len(ui_st.ev_args) <= depth { push(ui_st.ev_args, Value.list()) }
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let args = ui_st.ev_args[depth]
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Value.clear(args)
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ui_st.ev_depth = depth + 1
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for i in 0 .. len(x.args) { Value.add(args, ui_eval(ui_st, x.args[i], e)) }
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let r = ev_call_with(ui_st, x, e, args)
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ui_st.ev_depth = depth
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return r
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}
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# the call itself, its arguments evaluated; a callee reads them and keeps none
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function ev_call_with(ui_st: mut UiState, x: UiExpr, e: UiEnv, args: Val) -> Val {
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if x.s == "len" and len(x.args) == 1 { return uv_int(ui_st, Value.count(Value.at(args, 0))) }
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if x.s == "range" and len(x.args) == 1 {
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let out = uv_list(ui_st)
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for i in 0 .. Value.as_int(Value.at(args, 0)) { Value.add(out, uv_int(ui_st, i)) }
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return out
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}
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var at = e
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while at != null {
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if at.inst != null {
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let r = at.inst.cls.call(at.inst.ptr, x.s, args, uv_hold(ui_st))
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if Value.kind(r) != 99 { return r }
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}
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at = at.parent
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}
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if ui_st.ui_view == null or ui_st.ui_view.call == null {
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ui_err(ui_st, `{x.s}(): there is no function or event of that name here`)
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return Value.null()
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}
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return ui_st.ui_view.call(x.s, args)
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}
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function ui_eval_text(ui_st: mut UiState, x: UiExpr, e: UiEnv) -> string { return vl_text(ui_eval(ui_st, x, e)) }
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function ui_eval_bool(ui_st: mut UiState, x: UiExpr, e: UiEnv) -> bool { return vl_truthy(ui_eval(ui_st, x, e)) }
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