Pine Script v4/v5 平滑循环RSI添加EMA信号线报错修复

尝试在v4版本循环平滑RSI（Cyclic Smoothed RSI）指标上添加带平滑线的EMA信号指标，所用EMA代码为Pine Script v5版本，将EMA代码降级适配v4后运行出现报错：

Syntax error: Arguments of input function must be of constant type, or 'source' builtin variables.

若直接将代码升级到v5版本，又会出现iff()函数相关报错：

line 44: Could not find function or function reference 'iff'.

原v4版本代码如下：

//@version=4
study(title="Smoothed Cyclic RSI with EMA", shorttitle="cRSI-EMA")
src = close
domcycle = input(20, minval=10, title="Dominant Cycle Length")
crsi = 0.0
cyclelen = domcycle / 2
vibration = 10
leveling = 10.0
cyclicmemory = domcycle * 2
//set min/max ranges?

h1 = hline(30, color=color.silver, linestyle=hline.style_dashed)
h2 = hline(50, color=color.silver, linestyle=hline.style_dashed)
h3 = hline(70, color=color.silver, linestyle=hline.style_dashed)

torque = 2.0 / (vibration + 1)
phasingLag = (vibration - 1) / 2.0

up = rma(max(change(src), 0), cyclelen)
down = rma(-min(change(src), 0), cyclelen)
rsi = down == 0 ? 100 : up == 0 ? 0 : 100 - 100 / (1 + up / down)
csrsi = torque * (2 * rsi - rsi[phasingLag]) + (1 - torque) * nz(crsi[1])

lmax = -999999.0
lmin = 999999.0
for i = 0 to cyclicmemory - 1 by 1
    if nz(csrsi[i], -999999.0) > lmax
        lmax := nz(csrsi[i])
        lmax
    else
        if nz(csrsi[i], 999999.0) < lmin
            lmin := nz(csrsi[i])
            lmin

mstep = (lmax - lmin) / 100
aperc = leveling / 100

db = 0.0
for steps = 0 to 100 by 1
    testvalue = lmin + mstep * steps
    above = 0
    below = 0
    for m = 0 to cyclicmemory - 1 by 1
        below := below + iff(crsi[m] < testvalue, 1, 0)
        below

    ratio = below / cyclicmemory
    if ratio >= aperc
        db := testvalue
        break
    else
        continue

ub = 0.0
for steps = 0 to 100 by 1
    testvalue = lmax - mstep * steps
    above = 0
    for m = 0 to cyclicmemory - 1 by 1
        above := above + iff(crsi[m] >= testvalue, 1, 0)
        above

    ratio = above / cyclicmemory
    if ratio >= aperc
        ub := testvalue
        break
    else
        continue

fill(h1, h2, color=color.silver, transp=90)
plot(csrsi, "CS-RSI", color.fuchsia)

//EMA with Signal
//Inputs
len = input(9, minval=1, title="Length")
esrc = input(csrsi, title="Source")
smoothingLength = input(title = "Length", defval = 5, minval = 1, maxval = 100, group="Smoothing")
offset = input(title="Offset", defval=0, minval=-500, maxval=500)
//Calculation
out = ema(esrc, len)
smoothingLine = sma(out, smoothingLength)
//Plotting
plot(out, title="EMA", color=color.green, offset=offset)
plot(smoothingLine, title="Smoothing Line", color=color.red, offset=offset, display=display.none)

• v4版本input报错：Pine Script中input()函数的默认值仅支持常量或内置行情源变量（如close/open等），原代码直接将动态计算得到的自定义序列csrsi作为input默认值，不符合语法规则。
• v5版本iff报错：Pine Script v5已正式移除iff()函数，统一使用三元运算符实现等价条件判断逻辑。
• 隐藏逻辑bug：原代码计算高低位阈值的循环中，错误引用了未赋值的crsi变量，且相位滞后参数计算结果为浮点数，作为K线索引引用时会触发类型报错。

//@version=5
indicator(title="Smoothed Cyclic RSI with EMA", shorttitle="cRSI-EMA", overlay=false)
src = close
domcycle = input.int(20, minval=10, title="Dominant Cycle Length")
crsi = 0.0
cyclelen = domcycle / 2
vibration = 10
leveling = 10.0
cyclicmemory = domcycle * 2

h1 = hline(30, color=color.silver, linestyle=hline.style_dashed)
h2 = hline(50, color=color.silver, linestyle=hline.style_dashed)
h3 = hline(70, color=color.silver, linestyle=hline.style_dashed)

torque = 2.0 / (vibration + 1)
phasingLag = math.round((vibration - 1) / 2.0)

up = ta.rma(math.max(ta.change(src), 0), cyclelen)
down = ta.rma(-math.min(ta.change(src), 0), cyclelen)
rsi = down == 0 ? 100 : up == 0 ? 0 : 100 - 100 / (1 + up / down)
csrsi = torque * (2 * rsi - rsi[phasingLag]) + (1 - torque) * nz(crsi[1])

lmax = -999999.0
lmin = 999999.0
for i = 0 to cyclicmemory - 1 by 1
    if nz(csrsi[i], -999999.0) > lmax
        lmax := nz(csrsi[i])
    if nz(csrsi[i], 999999.0) < lmin
        lmin := nz(csrsi[i])

mstep = (lmax - lmin) / 100
aperc = leveling / 100

db = 0.0
for steps = 0 to 100 by 1
    testvalue = lmin + mstep * steps
    below = 0
    for m = 0 to cyclicmemory - 1 by 1
        below := below + (csrsi[m] < testvalue ? 1 : 0)

    ratio = below / cyclicmemory
    if ratio >= aperc
        db := testvalue
        break

ub = 0.0
for steps = 0 to 100 by 1
    testvalue = lmax - mstep * steps
    above = 0
    for m = 0 to cyclicmemory - 1 by 1
        above := above + (csrsi[m] >= testvalue ? 1 : 0)

    ratio = above / cyclicmemory
    if ratio >= aperc
        ub := testvalue
        break

fill(h1, h2, color=color.new(color.silver, 90))
plot(csrsi, "CS-RSI", color=color.new(color.fuchsia, 0))

//EMA with Signal
//Inputs
len = input.int(9, minval=1, title="EMA Length")
smoothingLength = input.int(title = "Smoothing Length", defval = 5, minval = 1, maxval = 100, group="Smoothing")
offset = input.int(title="Offset", defval=0, minval=-500, maxval=500)
//Calculation
out = ta.ema(csrsi, len)
smoothingLine = ta.sma(out, smoothingLength)
//Plotting
plot(out, title="EMA", color=color.new(color.green, 0), offset=offset)
plot(smoothingLine, title="Smoothing Line", color=color.new(color.red, 0), offset=offset, display=display.none)

• 全量适配v5语法：将study替换为indicator，通用输入函数替换为类型明确的input.int，所有技术计算函数归入ta命名空间，颜色、透明度参数适配v5规范，删除循环中多余的无意义返回行。
• 解决input类型报错：删除原代码中错误的esrc = input(csrsi, title="Source")行，由于EMA计算源固定为csrsi，无需额外提供源选择输入，直接将csrsi传入EMA计算函数即可，从根源规避input参数类型限制。
• 解决iff函数报错：将所有iff(cond, val1, val2)写法替换为等价三元运算符cond ? val1 : val2，符合v5语法要求。
• 修复隐藏逻辑问题：将循环中错误引用的未赋值变量crsi统一替换为计算完成的csrsi序列；对phasingLag增加取整逻辑，保证K线索引为整数，避免历史值引用报错。

内容的提问来源于stack exchange，提问作者Krishnendu Bhattacharyya