Q | Using Regex and eachmatch() to extract substrings

General Usage
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1

Hello,

I’m using a package [Form 4.3.0] for symbolic code optimization that outputs results in C and have written a script to convert the code to Julia.

It’s worked to-date, however, I’ve run into a new problem in recent use which is summarized in the following MWCE:

# test_string_match.jl

begin
    # c_rhs_str = "x*pow(w[2],4)"
    c_rhs_str = "pow(x,2)*pow(w[2],4)"

    rgx = r"pow\((.*),(.*[^.*])\)"

    regex_match = collect(eachmatch(rgx, c_rhs_str, overlap = false))

    for ith_match in regex_match
        @show pow_substr = ith_match.match
        @show rgx_vrbl, rgx_expnt = match(rgx, pow_substr)
    end
end

c_rhs_str = "x*pow(w[2],4)" = "x*pow(w[2],4)"
pow_substr = ith_match.match = "pow(w[2],4)"
(rgx_vrbl, rgx_expnt) = match(rgx, pow_substr) = RegexMatch("pow(w[2],4)", 1="w[2]", 2="4")

gives the expected result, however,

c_rhs_str = "pow(x,2)*pow(w[2],4)" = "pow(x,2)*pow(w[2],4)"
pow_substr = ith_match.match = "pow(x,2)*pow(w[2],4)"
(rgx_vrbl, rgx_expnt) = match(rgx, pow_substr) = RegexMatch("pow(x,2)*pow(w[2],4)", 1="x,2)*pow(w[2]", 2="4")

does not give the result I thought I would get

pow_substr = ith_match.match = “pow(x24)”
(rgx_vrbl, rgx_expnt) = match(rgx, pow_substr) = RegexMatch(“pow(x,4)”, 1=“x”, 2=“2”)
pow_substr = ith_match.match = “pow(w[2],4)”
(rgx_vrbl, rgx_expnt) = match(rgx, pow_substr) = RegexMatch(“pow(w[2],4)”, 1=“w[2]”, 2=“4”)

with the two pow() parsed into separate substrings.

So I’m wondering if this is a problem with my use of Regex or eachmatch() or both?

2

This doesn’t answer your regex question, but it looks like Form output is largely valid Julia syntax. Perhaps you need to do a few minor transformations like replace(s, "**"=>"^"), but assuming you have, you could use Meta.parse(s) to convert it to (quoted) Julia code.