dsl_preprocess: DSL preprocessing functions

In mrgsolve: Simulate from ODE-Based Models

DSL preprocessing functions

Description

These functions preprocess model code written in the mrgsolve DSL before C++ compilation.

Usage

convert_pow(x, block = "")

warn_int_div(x, block = "")

convert_fort_if(x)

convert_semicolons(x)

Arguments

x	character vector of source lines to process.
block	model block name; included in warning messages when called during model parsing.

Details

• convert_pow(): converts Fortran-style exponentiation (⁠**⁠) to C++ pow() calls; runs by default unless turned off by environment variable; lines of code will pass through unaltered if ⁠**⁠ is not found.

• warn_int_div(): warns about literal integer division (e.g. 3/4, 1/2) that truncates toward zero in C++; returns x invisibly and is called for its side-effect warnings; runs by default unless turned off by environment variable.

• convert_fort_if(): converts Fortran IF/THEN/ELSE/ENDIF constructs and relational operators (.GE., .LE., etc.) to C++; runs only when the nm-vars plugin is invoked.

• convert_semicolons(): appends semicolons to statement lines that are missing them; lines ending with an operator (e.g., + or / or "=") will not be terminated with a semicolon; this preprocessor must be enlisted through the semicolons plugin and it only runs with nm-vars; the semicolons plugin is brought online when the nm-like composite plugin (nm-vars, autodec, semicolons) is invoked.

Processing is controlled by environment variables:

• MRGSOLVE_CONVERT_POW (default TRUE)

• MRGSOLVE_CONVERT_FORT_IF (default TRUE)

• MRGSOLVE_WARN_INT_DIV (default TRUE)

Set any variable to FALSE to disable the corresponding step when processing a model file via mread(). Adding semicolons must be opted into through the semicolons or nm-like plugins.

Examples

convert_pow("a**2")
convert_pow("(WT/70) ** THETA(3)")

code <- c("IF ( WT .GE.90) THEN", "  CL = CL * 0.8", "ENDIF")
cat(code, sep = "\n")
cat(convert_fort_if(code), sep = "\n")

convert_semicolons("CL = THETA1")

code <- c("CL =", "THETA1 *", "(WT/70) *", "exp(ETA(1))")
cat(code, sep = "\n")
cat(convert_semicolons(code), sep = "\n")

warn_int_div("THETA(1) * pow(WT/70, 3/4)")
warn_int_div("3.0/4")

mrgsolve documentation built on May 20, 2026, 9:06 a.m.