Migrating from Make¶

A practical guide to converting Makefiles to Mustfile.toml.

Concept mapping¶

Make	must
`Makefile`	`Mustfile.toml`
`target: deps`	`[recipe.target]` with `deps`
Recipe body (tab-indented)	`script = "..."`
`$(VAR)` / `${VAR}`	`${VAR}` (same syntax)
`.PHONY: clean`	`phony = true`
`$(MAKE) -C subdir`	`workdir = "subdir/"`
`ifeq` / `ifdef`	`[env.<profile>]` or recipe-level `env`
`include other.mk`	`[include] paths = [...]`
`@echo "message"`	`script = "echo 'message'"`
Pattern rules (`%.o: %.c`)	No equivalent — use a loop or first-class type
`$(shell ...)`	Use must's built-in variable expansion
`$@`, `$<`, `$^`	Expanded inline during import

Step-by-step migration¶

1. Import¶

must import Makefile

This generates Mustfile.toml and import-report.md.

2. Review the import report¶

Check for:

Pattern rules that need manual conversion
Complex variable expansions
Implicit dependencies

3. Convert to first-class types¶

Replace generic shell recipes with language-specific types:

# Before
[recipe.build]
type   = "shell"
script = "cargo build --release -p my-app"

# After
[recipe.build]
type    = "rust-bin"
package = "my-app"

4. Move variables to [env]¶

# Makefile
CFLAGS := -O2 -Wall
TARGET := my-app

# Mustfile.toml
[env]
CFLAGS = "-O2 -Wall"
TARGET = "my-app"

5. Convert phony targets¶

# Makefile
.PHONY: clean test
clean:
    rm -rf build/
test:
    cargo test

# Mustfile.toml
[recipe.clean]
type   = "shell"
phony  = true
script = "rm -rf build/"

[recipe.test]
type    = "rust-test"
package = "my-app"

6. Remove tab indentation¶

must uses TOML strings — no tab-significant whitespace.

Side-by-side comparison¶

Makefile:

CFLAGS := -O2 -Wall
SRC    := $(wildcard src/*.c)
OBJ    := $(SRC:.c=.o)

my-app: $(OBJ)
    $(CC) $(CFLAGS) -o $@ $^

%.o: %.c
    $(CC) $(CFLAGS) -c $< -o $@

.PHONY: clean test
test: my-app
    ./my-app --test

clean:
    rm -f $(OBJ) my-app

Mustfile.toml:

[project]
name = "my-app"

[env]
CFLAGS = "-O2 -Wall"

[recipe.build]
type    = "c-bin"
sources = ["src/*.c"]
includes = ["src/"]

[recipe.test]
type   = "shell"
deps   = ["build"]
phony  = true
script = "./my-app --test"

[recipe.clean]
type   = "shell"
phony  = true
script = "rm -f src/*.o my-app"