regex

Compile string patterns to regex via ↦ regex.

Syntax: <string> ↦ regex

Category#

literal

Related#

• read
• conversio
• format

Examples#

radix/corpus/literalia/regex.fab (canonical · conversio)#

Compile string patterns to regex via ↦ regex.

# =============================================================================
# regex — Compile string patterns to regex via ↦ regex.
# =============================================================================
#
# What this teaches:
#   • converting string strings to compiled regex with `↦ regex`
#   • inline regex flags like `(?i)` for case-insensitive matching
#   • combining `§` template application with regex conversion for dynamic patterns
#
# Common mistakes:
#   • Forgetting that ↦ regex requires a string or ascii source — int and other types must convert to string first.
#
# See also: read, conversion, format
# =============================================================================

# literalia/regex — string ↦ regex conversion
#
# GRAMMAR:
#   conversion :← stringLit '↦' 'regex'
#   templateExpr :← stringLit '(' exprList ')'   -- then ↦ regex on the string result
#
# EXPECTED OUTPUT:
#   Regex pattern diagnostics for literals, inline flags, and a template-built path.
#
# BACKEND:
#   Cross-ref read/lege.fab for regex beside stdin reads.
#   Cross-ref format/scriptum.fab for § template application.

main {
    const regex digits ← "\d+" ↦ regex
    print digits
    const regex word ← "(?i)\w+" ↦ regex
    print word

    # Template application → string, then conversion to regex (dynamic path segments)
    const string tenant ← "acme"
    const regex homePath ← "/home/§/.*"(tenant) ↦ regex
    print homePath
}

Expected output:

\d+
(?i)\w+
/home/acme/.*